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Kryptonite

Kryptonite is a mineral from the Superman mythos, originating in the Superman radio show series.

The material is usually shown as having been created from the remains of Superman's native planet of Krypton, and generally has detrimental effects on Superman and other Kryptonians. The name "Kryptonite" covers a variety of forms of the substance, but usually refers to the most common "green" form.

The word Kryptonite is also used in modern speech as a synonym for Achilles' heel, the one weakness of an otherwise invulnerable hero.

Fictional history

Original versions

A forerunner of the kryptonite concept was the unpublished 1940 story "The K-Metal from Krypton", by Superman co-creator Jerry Siegel. The K-metal in the story was a piece of Krypton which robbed Superman of his strength while giving humans superpowers, a plot point which made its way into the tv series Smallville.

"Kryptonite" was introduced in 1943 on the Superman radio series, as both a plot device and to allow Superman's actor, Bud Collyer, to occasionally take time off. The substance played a part in at least one major plot-line during the course of the program.

It was not until 1949 that the comic book writers incorporated it into their stories, as both a convenient danger and weakness for Superman and to add an interesting element to his stories. Kryptonite is most commonly depicted as green in coloring, with a few exceptions; it was red in its first appearance in Superman (volume 1) #61 in 1949. When Superman followed the time trail of a piece of red rock that weakened him, he was able to trace his origin back to Krypton for the first time. Other colors of kryptonite, having different effects, began to show up frequently beginning in late 1950s comics, reaching a peak in appearances in 1960s Superman series.

Kryptonite was depicted as being so abundant that many ordinary criminals kept a supply as a precaution against Superman's interference. They kept it hidden so Superman would not be able to steal it and destroy it. In an effort to reduce the use of kryptonite in Superman storylines, all known kryptonite on Earth was transmuted into k-iron in a 1971 storyline, though kryptonite could still be synthetically manufactured by a variety of known and unknown means, and additional material left over from the destruction of Krypton would continue to fall from space.

Post-Crisis Versions

While quantities of Kryptonite are reduced, the material is still present Post-Crisis, albeit only in its green form. However, through the use of Batman's notes, Ra's al Ghul is able to fashion a synthetic Red Kryptonite. Even after quantities have been reduced there's still a fair amount of Kryptonite available, which prompts Superman-friendly corporations, such as Wayne Enterprises and Kord Industries, to take it upon themselves to round up all remaining pieces so as to make its acquisition by small-time crooks more difficult.

After the second recreation of the Multiverse, the amount of Kryptonite on Earth skyrockets, carried down to Earth in a huge meteorite by the rocket that brought Kara to Gotham City.

In the recreated Universe Kryptonite is in such abundance that it becomes easily available to ordinary criminals and crooks, as before. Following orders issued by Lex Luthor and Lana Lang, LexCorp starts stockpiling it and selling to government facilities and weapon makers. Superman and Batman embark on a mission to rid Earth of Kryptonite; a mission that almost fails when the cornered Lana Lang launches a large number of dirty Kryptonite warheads, all simultaneously, tainting the whole Earth atmosphere. Hiro Okamura builds and frees a storm of nanobot devised to capture and deactivate the tiniest fragments of Kryptonite.

Once again, as in the 1971 storyline, all Kryptonite is destroyed, the remaining fragments wrapped in lead and hurled into the Sun by Superman himself, save for one fragment, which Superman gives to Batman. However, it is later revealed that Batman has acquired a fair amount of every variety of the alien material, keeping his samples in the Batcave

The Science Behind Kryptonite

Despite the matching name, it was never suggested that the element krypton had any significance to the name of the planet Krypton.

Under standard chemical naming procedures, the -ite suffix of kryptonite would denote an oxyanion of the element krypton. However, krypton is a noble gas that forms compounds only with great difficulty, and such an oxyanion is not known. (Nevertheless, the University of Leicester presented the Geological Society with krypton difluoride to commemorate the 70th anniversary of Superman )

The term kryptonite instead implies a meteorite from the planet Krypton, as in the Lois and Clark: The New Adventures of Superman episode "The Green, Green Glow of Home", where it is given as "period element 126", which in reality corresponds to unbihexium/eka-plutonium, the most stable of the elements in the so-called island of stability. Superman: The Man of Steel Sourcebook (1992), while non-canon, concurs, referring to kryptonite as "the common ore of the super-actinide kryptonium, an unusually stable transuranic element, whose atomic number is believed to be 126". Kryptonium is given a radioactive half-life of 250,000 years.

In Superman Returns, Lex Luthor steals a fragment of kryptonite from a Metropolis museum, where it is on display under the title 'Sodium lithium boron silicate hydroxide with fluorine'. As borosilicate glass is commonly crystalline and green-tinted, this could be a plausible human mis-identification of kryptonite; alternately, as no 'unknown' component is listed, one might assume this blend to be the actual composition of green kryptonite. Real sodium lithium boron silicate hydroxide (without fluorine), Jadarite, was discovered in a Serbian mine in April 2007, and takes the form of a white powder rather than large green crystals.

In Superman: The Movie, Lex Luthor describes Superman's enhanced Kryptonian physiology as being vulnerable to kryptonite's particular radioactive "signature". More recently, some issues of Superman indicate the mechanism by which green kryptonite may hurt Superman. Superman's cells absorb electromagnetic radiation from stars (like Earth's sun). Kryptonite's radioactivity interferes with this semi-photosynthetic process, driving the energy out of his cells in a painful fashion.

Long-term exposure to kryptonite is said to have the same effects on human beings as exposure to other radioactive materials; an extended storyline in the comics around 1990 involved Lex Luthor developing cancer from the kryptonite ring he kept on his finger.

Forms of kryptonite

Variations

The various known forms of Kryptonite in the Superman comics:

Colors of Kryptonite	Effects
Green Kryptonite	The most common form of kryptonite, created by the "radioactive chain reaction" which destroyed Krypton, and "scattered throughout space as meteors." In superpowered Kryptonians, causes immediate physical pain and debilitation, reduces their powers, and kills within hours. Green kryptonite is a radioactive substance and as such, prolonged exposure to green kryptonite can cause cancer in humans. Green kryptonite has been shown to strengthen Bizarro. Lead as well as normal containment methods for radioactive substances has been shown to block kryptonite radiation. In the Superman movie continuity and the television series Lois & Clark: The New Adventures of Superman, green kryptonite is shown as effectively removing Superman's powers during the time he is exposed. In Lois & Clark he remains as vulnerable to injury as a human for a few minutes afterward. In most comics continuity, however, Superman retains his powers to some degree while exposed to green kryptonite, although dramatically weakened and in severe pain. His skin also begins to turn green. In various stories, Superman is shown to have become immune to the effects of green kryptonite either to repeated non-fatal exposure, continuous long-term absorption of solar radiation or extremely high short-term exposure to the Sun. Green kryptonite is typically shown to have no short-term effects on humans or non-superpowered Kryptonians. However, in post-Crisis continuity, long-term exposure can cause radiation poisoning in humans. In Smallville, green kryptonite can cause normal humans to mutate and acquire superhuman abilities, although an outside catalyst (such as a strong electrical charge) is usually required. In the episode "Void", kryptonite injections cause near-death experiences in humans. After Clark is injected with kryptonite and apparently dies, Chloe reports "actually dying neutralizes the kryptonite in your system". Green kryptonite, being radioactive, has been used as an energy source to power reactors in power stations. The supervillain Metallo uses green kryptonite to power his cyborg body.
Red Kryptonite	No two chunks of red kryptonite have the same, "unexpected," effect on Kryptonians. In one episode of Superfriends, 3 Kryptonian criminals exposed at the same time were all affected differently. Effects are typically depicted to last for 1-2 Days, after which the Kryptonian in question is always immune to that specific chunk of red kryptonite. However, in some incarnations the effects of red kryptonite last only as long as the Kryptonian is exposed to it. Pre-Crisis red kryptonite was created from a "flock" of green kryptonite which passed through a (red-hued) "strange cosmic cloud," some of which arrived on Earth. In post-Crisis continuity, red kryptonite first appears as an artificial construct of Mr. Mxyzptlk, then as a synthetic variant created by Ra's al Ghul, using notes stolen from Batman. Superman has suffered the following random effects upon exposure to various pieces of red kryptonite: being turned into a dragon, a non-powered giant, a dwarf, an ant-headed humanoid, a lunatic, and an amnesiac; being made unable to see anything colored green; growing incredibly long hair, nails, and beard; being rendered totally powerless; growing fat; gaining the ability to read thoughts; growing a third eye in the back of his head; losing his invulnerability along the left side of his body; being split into an evil Superman and a good Clark Kent; being split into young and old forms (Superboy and Superman); being rendered unable to speak or write anything but Kryptonese; growing an extra set of arms; becoming clumsy; swapping bodies with the person nearest him upon exposure to it; transferring his powers; rapidly aging; multiple personality changes; and having his skin rendered transparent, overloading him with solar power. In Lois and Clark: The New Adventures of Superman, red Kryptonite initially caused Superman to become apathetic. He simply did not care about catching criminals; instead shrugging his shoulders, blaming others and talking to a girl. It was hypothesized that, given enough exposure to red Kryptonite, Clark's condition would become permanent. However, after talking to a psychiatrist, Clark was able to resist the effects of the red Kryptonite, and he picked up the rock and threw it out of a window. Its later appearances included a red Kryptonite laser which caused Superman's powers to transfer to Lois, and exposure causing Superman's powers to be increased beyond his ability to control them. On the TV series Smallville, red kryptonite has a drug-like effect, causing severe changes in Clark Kent's personality. Under this influence, Clark loses his inhibitions, becoming unpredictable and acting purely on erotic and selfish emotions. Smallville red kryptonite requires close contact with skin to be effective. In Krypto the Superdog, effects on Krypto include temporary amnesia, losing all super powers, causing Krypto's tail to detach from his body and come to life, and body-swapping.
Gold Kryptonite	Permanently removes superpowers from Kryptonians, by destroying the ability of Kryptonian cells to process solar energy. For obvious reasons, this variety is little-used in Superman stories. Gold Kryptonite appears in The Flash (vol. 1) #175 and plays a key role in the 1982 limited series "The Phantom Zone", as well as the 1986 "imaginary story" Superman: Whatever Happened to the Man of Tomorrow?, a possible conclusion to the story of Superman of Earth-One. Post-Crisis, gold kryptonite has appeared in Adventures of Superman #444 and Superman (vol. 2) #22. In the Legion of Super-Heroes (vol. 2) #293, during the Great Darkness Saga, it is shown that Element Lad can transmute matter into gold kryptonite. In one instance, gold kryptonite is shown to instead cause cellular degeneration and accelerated aging; however, it is not confirmed if this is true of all gold kryptonite because this version was presumably created by the time traveller Gog. In Action Comics Annual #11, Metallo mentions that the Gold Kryptonite in his chest only temporarily removes a Kryptonian's powers.
Blue Kryptonite	Blue kryptonite is the Bizarro analogue to green kryptonite. Using Bizarro logic, this, in general, hurts Bizarros while having beneficial effects on ordinary Kryptonians. Pre-Crisis, blue kryptonite is the result of using Professor Potter's "duplicator ray" on some green kryptonite. Here, blue kryptonite affects Bizarros like green kryptonite affects Kryptonians. Blue Kryptonite radiation is not blocked by normal lead but by imperfectly duplicated lead. Bizarro World, a sentient planet, had animated Blue Kryptonite golems underground that surfaced and attacked the Super-Powered Bizarros while the delighted non-powered bizarros cheered them on. Exposure to Blue Kryptonite radiation turned the mind of the original Jimmy Olsen when his mind was turned to that of a Bizarro, back to his normal state of mind. In an episode of Super Friends, blue kryptonite heals Superman from the effects of red kryptonite. Post-Crisis, its origin is unknown. Here, blue kryptonite makes Bizarros become polite, goodhearted, coherent, and intelligent. It also causes physical pain much like green kryptonite affects Superman. In Smallville, blue kryptonite suppresses Kryptonians powers and removes their sensitivity to green kryptonite. Blue Kryptonite is therefore not a reverse analogue of Green Kryptonite. Blue Kryptonite was first introduced as a Victory Ring given to Clark by a replicant of Lara El in "Blue". Also in Smallville, the Phantom Bizarro's powers were increased exponentially by blue kryptonite, overloading his powers and killing him, much like "a light bulb being powered by a nuclear reactor", in the episode "Persona". This is due to the reverse effect of kryptonite on Bizarro - where it causes Clark to lose his powers, it gives Bizarro new and immense power. Blue kryptonite has also been used in Superman video games as a life restorative due to its bizarro nature.
Black Kryptonite	Black Kryptonite was first introduced in the Smallville television series, in the fourth season premiere episode "Crusade", as Kryptonite with the ability to split the personality of Kryptonians. It later appears in the fourth season episode "Onyx", where it is revealed to split physically the bodies of humans. In the series, Black Kryptonite can be created by super-heating Green Kryptonite. It later made its first appearance in a DC comic in September 2005's Supergirl #2, where it apparently possessed the ability to split a person or a person's personality into two separate entities. In Supergirl #3, Luthor used Black Kryptonite on Supergirl, which caused her to split into two separate people, one wearing Supergirl's traditional costume, and another wearing a black-and-white version. Her black-and-white costume is similar to the one that Superman was wearing when he returned from the dead. Luthor noted that he was given the Black Kryptonite by the self-proclaimed god Darkseid, who may have been responsible for its creation (a synthesized version of Kryptonite in the feature film Superman III had similar effects on Superman, creating an evil Superman). In All-Star Superman, which takes place outside of DC Universe continuity, Black Kryptonite makes Superman evil, almost as if he is transforming into Bizarro Superman.
White Kryptonite	Kills all plant life, whether Kryptonian or not. Induces decay immediately upon exposure, with a range of about 25 yards. The most prominent use of this variety in the comics was to destroy Virus X, which was revealed in a storyline in 1968's Action Comics #362-366 to actually be a form of plant life.
Jewel Kryptonite	Jewel Kryptonite amplifies the psychic powers of Phantom Zone residents, allowing them to project illusions into the "real world" or perform mind control. It was made from what was left of a mountain range on Krypton called the Jewel Mountains. In the post-Crisis Silver Age limited series, a "prismatic gem from the Jewel Mountains of Krypton" was used by the Injustice League to amplify the psychic powers of the Absorbascon, but was not referred to as Jewel Kryptonite.
Anti-Kryptonite	Has no effect on superpowered Kryptonians, but has the same effects as Green Kryptonite on non-superpowered Kryptonians. This version of Kryptonite is what killed most of the residents of Argo City in the pre-Crisis comics. Anti-Kryptonite was likely introduced to cover a writer error, as in the original Argo City story, the residents of Argo City are killed by Green Kryptonite even though it should have had no effect on non-superpowered Kryptonians. Post-Crisis, it is the power source of Ultraman, Superman's evil counterpart who lives in an alternate antimatter universe. Anti-Kryptonite was also used by Green Lantern Hal Jordan while rescuing a member of the Green Lantern Corps (Guy Gardner) from the Phantom Zone to cause pain to General Zod, Kru-El, and Faora (since regular Kryptonite has no effect on individuals in the Phantom Zone). This was shown in the Green Lantern comic book series of the 1980s.
X-Kryptonite	Created accidentally (and unknowlingly) by pre-Crisis Supergirl during experimentation with Green Kryptonite, in an attempt to find an antidote. The "unique combination of chemicals" used by Supergirl created "something new under the sun," whose radiation (and odor) can imbue Earth-based lifeforms with temporary superpowers. It has no additional effect on Kryptonians (although the latent kryptonite radiation is still harmful to them), and is primarily known as the source Supergirl's pet cat, Streaky's superpowers. Not to be confused with Kryptonite-X.
Slow Kryptonite	A modified variety of Green Kryptonite produced by supervillain Metallo that affects humans in a manner similar to normal Green Kryptonite on Kryptonians, appearing in The Brave and the Bold #175. Its effect on Kryptonians, if any, is undocumented.
Magno-Kryptonite	Artificially created by the villain Nero, "Magno-Kryptonite" is magnetically attracted to all substances originally from Krypton, with such incredible force that not even the strength of Superman or Bizarro can escape it according to Superman's Pal, Jimmy Olsen #92. It is not specifically stated if any parts of its alloy are of Kryptonian origin.
Bizarro Red Kryptonite	Affects humans the same way Red Kryptonite affects Kryptonians. Appeared in Superman's Pal, Jimmy Olsen #80.
Kryptonite-X or Kryptisium	A form of filtered/purified Kryptonite. Professor Emil Hamilton used the term "Kryptonite-X" (The Adventures of Superman #511, April 1994, page 13) to describe the substance that restored Superman's powers after a confrontation with the villain known as the Cyborg Superman in Engine City (Superman v2, #82, part of the "Return of Superman" storyline). This substance was created when the Cyborg used a huge chunk of Kryptonite in an attempt to kill the weak, powerless, recovering Superman. The Eradicator, who had fashioned a faux-Kryptonian body using a Kryptonian matrix, jumped in front of Superman before the release of the Kryptonite energy could kill him. Despite the Eradicator's efforts, the Kryptonite energy hit Superman, but instead of killing him, it transferred all of the characteristic Kryptonian powers from the Eradicator to Superman, as well as saturating Superman's body with a purified/filtered form of Kryptonite. This substance eventually led to Superman becoming an over-muscled giant, due to his accelerated sunlight absorption and overstorage of energy. (This Kryptonite is not to be confused with X-Kryptonite.)
Silver Kryptonite	In the television show Smallville episode titled "Splinter," manufactured "silver kryptonite" brings out Clark's paranoid side, and his delusions show him some of his greatest fears, which he believes to be real. The effects of the kryptonite were removed by Dr. Fine (Brainiac) who sent the "silver meteor rock" to Lana in Lex's name to "help" her with her astronomy paper. Clark pricked his finger with the sharp edge of the rock as he held it while visiting Lana in her dorm room, causing him to feel the effects immediately. However, this "new form of kryptonite" turned out to be a hoax (see Smallville entry below).
Magic Kryptonite	In Superman/Batman #46, an enchanted piece of Kryptonite has effects similar to Marijuana, until Batman finds another piece which cancels out the effects of the first piece. The first piece is a silver crescent. The second piece is a lavender round rock that fits into the crescent.
Pink Kryptonite	From Supergirl (vol. 2) #79, an alternate timeline in a 2003 Supergirl storyline by Peter David, this bizarre variety of Kryptonite apparently turned heterosexual Kryptonians temporarily and stereotypically gay; it was seen in just one panel, with Superman giving flattering compliments to Jimmy Olsen about his wardrobe and decorative sense. It spoofs the more "innocent times" of the Silver Age (Lois Lane is depicted in this story as not understanding what's gotten into Superman).

Simulated kryptonite

Green Lantern Corps power rings can be used to emit simulated green kryptonite radiation. Kyle Rayner did so in Man of Tomorrow #19 (1998). The duplicate Hal Jordan Green Lantern form of N'Gon also created Power Ring-based Green Kryptonite in "DC Comics Presents" #26 and Superman used the yellow of his cape's "S" design to block the effect. This radiation is apparently just as powerful and painful to Superman and other Kryptonians as the genuine rays, but it can be blocked by interposing anything yellow between the Green Lantern's green kryptonite and the Kryptonian (however, this may no longer be an option due to the recent development of yellow no longer being an automatic weakness of power rings). Breaking the ring-bearer's concentration will also dispel the effect.
Synthetic kryptonite (usually the green or red variety) has been successfully produced by Lex Luthor, Batman, and Ra's al Ghul in the comics. It has proven to be less powerful than genuine kryptonite, to be extremely difficult to create, and to have a short half-life that renders it useless after a short period of time. In the Elseworlds story Batman: The Dark Knight Returns, Green Arrow wounds Superman with a synthetic kryptonite arrow, allowing Batman to defeat him. Bruce Wayne notes it was very expensive to develop, taking years to properly synthesize. Superman III featured synthetic kryptonite that altered Superman's personality.
Magic: Individuals adept at the use of magic may be able to create kryptonite, such as Mr. Mxyzptlk did in the "Krisis of the Krimson Kryptonite" storyline (though his version of Red Kryptonite differed from the traditional version in its workings, temporarily eliminating Superman's powers). Jimmy Olsen, when changed into a Genie in Superman's Pal, Jimmy Olsen #42 (January 1960), was ordered by his master, Abdul, to turn himself into Living Kryptonite, Jimmy chose Green Kryptonite.
On one occasion, Lex Luthor combined the element-duplicating substance that composes the robots known as the Metal Men into a single robot that imperfectly duplicated the properties of green kryptonite. While its presence caused Superman severe pain, it was not severe enough to completely incapacitate him, and did not affect his powers at all; thus, Superman was able to focus past the pain and defeat the robot.
Radiation: In the film Superman III, the computer Webster built was able to analyze Superman and find his weakness, and emitted a beam of radiation that simulates that of green kryptonite. It was stopped only when Gus Gorman pulled the plug.

Hoaxes

In the comics and other media, some varieties of kryptonite that turned out to be hoaxes:

Silver Kryptonite: Featured in Superman's Pal, Jimmy Olsen #70, Silver Kryptonite is a hoax revolving around the silver anniversary of Superman's career. Silver Kryptonite in another form is a part of the Smallville TV series (see Smallville below), and was shown in the comics continuity in Superman/Batman #46.
Yellow Kryptonite: This one was used in a hoax masterminded by Lex Luthor Action Comics #277.
Blood Kryptonite: In 52, the Cult of Conner - a religious sect dedicated to resurrecting Superboy, employed "Blood Kryptonite" in a preliminary ritual to resurrect Sue Dibny. While physically resembling Green Kryptonite, the "Blood" variant drains a portion of life force from present attendees, intended to direct this energy towards an effigy of the deceased as part of a Kryptonian resurrection ceremony. It is later revealed that this was a manipulation of Felix Faust and the rock was either regular green Kryptonite or not Kryptonite at all.
Kryptonite Plus: 30 or so non-glowing, varicolored, banded rocks invading unnamed Super-aliens had left on Earth's moon and then said were Kryptonite Plus or maybe a form of Ultra-Kryptonite. They are really Tikron Stones. From Superman's Pal, Jimmy Olsen #126 (January 1970).
Purple Spotted Kryptonite: Mentioned in Streaky's fictional story in the animated cartoon Krypto the Superdog. This phony Kryptonite made Krypto chase his tail.
Fake Kryptonite: Seen in an episode of Superboy 1988 TV series, Superboy's friends are selling crystals which are labeled as "fake Kryptonite" to raise money for charity. These crystals are clearly false and the vendors make no dispute about it. However, they use humorous references such as "Buy one and have nothing to fear; even Superboy will run away from you!"

Other media

As noted above, kryptonite was originally created for the 1940s Superman radio series. Kryptonite has appeared in various forms in the various Superman media spinoffs, however.

Kryptonite was used in a rap song called Kryptonite by rapper Big Boi, but in the song kryptonite means marijuana because they are both green.

Kryptonite also appears in the 2000 3 Doors Down hit by the same title as well as the Five For Fighting 2000 song "Superman." Both songs deal with the often over-looked difficulties in being a superhero, depicting a trend in the superhero genre where these classic heroes--once seen as untouchable and, indeed, superhuman--are portrayed as flawed and troubled.

"Black Kryptonite" was what Will Smith described the Men in Black to be in the soundtrack to Men in Black II.

Professional wrestler Mike Bucci, who performed under a superhero gimmick called Super Nova, named his finishing move the "Kryptonite Krunch".

Depictions of kryptonite in the various films and TV series of Superman have largely been limited to green kryptonite, with occasional appearances of the red and blue varieties.

Adventures of Superman

Kryptonite was used in several episodes of Adventures of Superman, proceeding from straightforward to increasingly far-fetched plotlines. The specific color is not definite, given that it is never mentioned and that the series was initially in black & white, but from its effects, it is presumed to be green kryptonite in all cases:

In "Panic in the Sky", Superman’s attempt to shift a meteor hurtling toward earth leaves him with amnesia. Although the scientists in the episode only say the meteor consist of "unknown elements", a fragment of this meteor is later used in "The Deadly Rock", then referred to as Kryptonite.

In "The Defeat of Superman", an overacting scientist working for a crime boss synthesizes kryptonite after working out the formula from a tiny fragment found in a meteorite. As Superman lies dying from the metal's effects, Lois and Jimmy rescue him for once, sealing the block of kryptonite in a lead pipe, and Superman recovers. He then flings the pipe through the sky and into the sea with a super-throw. The escaping criminals, startled by the rocketing pipe, veer off the road and plummet to their deaths, keeping this dangerous secret "safe" in the hands of Superman's two friends.

In "Superman Week", Jimmy manages to blurt out the secret to the wrong listener. Superman stages an elaborate ruse in which he pretends to have retrieved the lead-encased metal from the ocean, and uses it to lead a wanted criminal into a trap. This ruse also presumably proves that Superman is not vulnerable to it, thus staving off criminals' thoughts of using it...for awhile.

In "The Deadly Rock", another eccentric scientist finds a meteorite that happens to be from Krypton, and a crime boss tries to use it to destroy Superman, who instead destroys it through the unlikely method of burning it with a flame-thrower.

In "The Magic Secret", yet another eccentric scientist teams with a criminal, this time tricking Superman into descending a narrow and deep well to rescue Lois and Jimmy, then proceeding to shower the Man of Steel with kryptonite particles.

In "The Gentle Monster", a very eccentric but good-natured scientist constructs a super-powered robot whose strength is derived from a chunk of the metal that the scientist has found, not knowing the danger it poses to Superman.

Movies

Kryptonite was featured in Superman: The Movie. In the film, Lex Luthor (Gene Hackman) and his cronies (Ned Beatty and Valerie Perrine) track a large chunk to Addis Ababa, Ethiopia, where they steal it from a museum under the cover of night. In this film's usage, the term "kryptonite" seems to mean simply a "Kryptonian meteorite". After co-opting and launching two missiles for opposite ends of the United States, Luthor places the kryptonite on a chain around Superman's (Christopher Reeve) neck and drops him into a swimming pool. When Perrine's character Miss Tessmacher learns that one of the missiles is headed for Hackensack, New Jersey (where her mother lives), she rescues Superman from drowning and removes the kryptonite, after which his strength and powers quickly return.

An imperfect synthesis of artificial kryptonite containing tar appeared in Superman III. Ross Webster (Robert Vaughn) orders the creation of synthetic kryptonite after remembering a Daily Planet story about the last original chunk disappearing years earlier after falling to Earth (whether Webster references the kryptonite robbery in Superman: The Movie is unclear.) Developed by Gus Gorman (played by Richard Pryor), it was intended to be a copy of Green Kryptonite. After scanning the coordinates of Krypton's former location via satellite, results return a small percentage of an unknown component. The substitution of tar (which Gorman used after glancing at a cigarette carton) for a crucial, but unknown, component resulted in the synthetic kryptonite behaving like a combination of Red Kryptonite and Black Kryptonite; in this case, the kryptonite turned Superman evil and eventually split him into two people. The evil Superman and Clark Kent, the embodiment of Superman's remaining good qualities, then engage in an epic battle at a deserted junkyard, where Clark emerges victorious and the evil Superman fades from sight (it should be noted that this might only have been an hallucination on Superman's part). Later in the film, Gorman's creation, the Ultimate Computer, severely weakens Superman with a kryptonite ray before Gorman has a change of heart and attacks his own machine.

In Superman Returns, an additional piece of kryptonite is found in a rock fragment, once more in Addis Ababa. Lex Luthor steals it from a Metropolis museum and uses it in his quest to create a new kryptonite landmass, much like how young Clark created the Fortress of Solitude. In addition, he uses a shard leftover from processing it to create a kryptonite shiv, which he uses to stab Superman with at one point. Interestingly, Kryptonite is never once referred to as the term "meteor" as it is in the previous movies and Smallville series, only as "distant remains" or "radioactive pieces of [Superman's] home-world". This may have been an attempt on the writers' part to distinguish the Kryptonite of the movie away from Smallville, which is almost always referred to as "meteors".

The Adventures of Superboy

Kryptonite made frequent appearances in the syndicated "Superboy" TV series, most of it green. It first appeared in the first-season episode "Kryptonite Kills" in which Professor Peterson retrieved it from Addis Adaba believing it to be a harmless meteorite and brought it to his gemology class at Shuster University. Superboy in his guise as Clark Kent(played by John Haymes Newton in Season 1, Gerard Christopher in Seasons 2-4), a student in Peterson's science class, collapsed from the radiation and felt its effects for the first time. He later threw most of the Kryptonite into space, except for one piece which was washed into the sewer. That piece was discovered by a mixed-up scientist who used it as a power source for Metallo (Roger Corben) in the second season episode "Metallo".

Green Kryptonite made several more appearances throughout the series, used mostly by Lex Luthor (played by Sherman Howard) and Metallo (played by Michael Callan). In the third season episode "Bride of Bizarro", Luthor sent Bizarro to a military research base to steal a large amount of Kryptonite, which Luthor was seen using on Superboy in later episodes. In the fourth season episode "Kryptonite Kid", a young man named Mike Walker (played by Jay Underwood) working at the same military research base was caught in a Kryptonite explosion while working to find a cure which would make Superboy immune to the radiation. The Kryptonite entered his bloodstream and turned his skin green and he became "living, breathing Kryptonite" able to fire Kryptonite radiation from his hands. In "Obituary for a Super-Hero", Luthor used a Kryptonite bomb planted on a yacht to attempt to kill Superboy.

Red Kryptonite made an appearance in the second season episode "Super Menace". This version of Red K was created at a military research base where scientists were working to neutralize Kryptonite's effect on Superboy while still retaining its radioactive properties so it could be used as a power source. Their experiments turned the Kryptonite red, making it useless as a power source and altering its effect on Superboy. This Red Kryptonite turned Superboy evil, much like Red K would later do in the "Smallville" TV Series, except only a single exposure to it was required, rather than constant exposure. After Superboy wreaked havoc with Metallo, Lana Lang (played by Stacy Haiduk) tricked Superboy into being exposed to another chunk of Red Kryptonite which reversed the effects of the first. This is Red Kryptonite's only appearance in the series, so it is unknown if the substance would have had other effects on Superboy if it had appeared again.

The "Superboy" series also introduced a form of White Kryptonite, however this was not the white kryptonite that kills plant life (as seen in the Pre-Crisis comic books). This White K was created by Professor Peterson's duplicating ray in an attempt to create a form of Kryptonite that would kill the molecularly unstable Bizarro. This Kryptonite did not kill Bizarro, however. It instead had an opposite effect on him and actually stabilized and cured him, preventing him from eventually exploding as previous Bizarro duplicates had. White Kryptonite made only one appearance in the series in the episode "The Battle With Bizarro". It is referred to again in "The Bride of Bizarro" but it is not seen.

Lois and Clark: The New Adventures of Superman

Kryptonite was used throughout the 1990s television series Lois and Clark: The New Adventures of Superman.

In "The Green, Green Glow of Home" the first piece was unearthed on the Smallville farm of Kent family friend Wayne Irig. He sent a sample of the rock to a local university. This came to the attention of Jason Trask. Trask headed Bureau 39, a secret government organization that investigated perceived alien threats. Trask had the paranoid belief that Superman was the first agent of an alien invasion. Understanding that the radioactive meteorite came from Krypton, he attempted to use the rock to kill Superman. Subsequently the main fragment of the meteorite was destroyed and Trask was killed by the local Sheriff. Consequently only Clark Kent and his parents knew of its true existence. Clark and his partner Lois Lane reported on the incident in The Daily Planet and described Trask's delusions of a fabled rock that could kill Superman. Ironically in this article it was Clark Kent himself who first named it "Kryptonite".

As shown in "Barbarians at the Planet" and "The House of Luthor" The story of kryptonite intrigued Superman's archenemy Lex Luthor. He used the many resources at his disposal to track down and confirm the existence of the original sample that Irig had sent to be studied. Luthor ground down part of this kryptonite and used it to coat the bars of a cage to entrap the Man of Steel. After Superman's escape from this kryptonite prison and Luthor's apparent death, the legend of kryptonite continued to grow.

Many criminals and former Lexcorp employees sought to acquire Luthor's kryptonite. In fact most of the kryptonite to be featured on the series originated from that first chunk found by Wayne Irig. During the 3rd season a new second piece was discovered, which Superman turned over to S.T.A.R. Labs for testing. This was the source of most of the kryptonite featured for the remainder of the series.

On Lois and Clark, green kryptonite was delivered in a variety of ingenious ways. A bullet was fashioned from pure kryptonite in one episode, and in another, a wicked woman tried to bring about Superman's demise by kissing him after coating her lips with a kryptonite-contaminated lipstick. In the episode "Metallo", scientist Emmett Vale, who studied Luthor's kryptonite while working at Lexlabs, used a piece to power the cyborg he created from fatally wounded criminal John Corben.

Red Kryptonite also was featured in the series. In one episode, it made Superman apathetic; in another, it transferred his powers to Lois Lane after being focused through a laser beam. In yet another, it uncontrollably supercharged his powers, causing him to do things such as accidentally fly through the sidewalk when landing. A renegade S.T.A.R. Labs scientist created a "Hybrid Kryptonite," which was just as deadly to humans as to Kryptonians.

Smallville

In the 2000s television series Smallville, the show expands on the concept of the substance being harmful to humans, as well as making extensive use of the substance. On the show, not only is green kryptonite (referred to in the first two seasons of the series as "meteor rock") harmful to Clark Kent, but it can produce bizarre changes in humans, animals, and plants, typically turning them into powerful mutant menaces, commonly known by the inhabitants of Smallville as "Meteor Freaks," that Clark must oppose. These changes seem to be linked to the circumstances under which the subject was exposed to kryptonite and the subject's emotional state (similar to how gamma radiation affects people in the Marvel Comics universe). Groups of people have been shown to acquire the same powers from kryptonite by exposing themselves to it in the same manner.

The harm inflicted on Clark by kryptonite on Smallville is varied. He cannot be near green kryptonite without doubling over in nausea and pain, and if he were to hold a fragment of it in his hand, it would burn to the touch and the veins in his hand would become exposed and green. However, on other separate occasions Clark has held and even ingested kryptonite (albeit in dilluted form) and been merely weakened. When a vial of Clark's blood was held up to kryptonite to verify its authenticity, the blood began to boil.

Red kryptonite has also been shown in Smallville. Its effect on Clark Kent is to rid him of all inhibitions, making him rebellious and potentially dangerous if exposed to it for too long. Also created for the series was black kryptonite (first appearing in the episode "Crusade"), which is capable of separating certain entities within individual organisms, e.g., splitting a person's good and evil sides.

Black kryptonite was formed by heating up green kryptonite. In the series, after Clark's "reprogramming" by Jor-El in the caves, Martha Kent used black kryptonite to reveal the two psyches of Clark, the militant Kal-El (not to be confused with the rebellious "Kal" alias caused by red kryptonite), and normal Clark. In a later episode, Lex Luthor was experimenting with a process to heat up green kryptonite and irradiate seeds, in order to separate the "weak" genes from the "strong" genes in the seeds. The result was hardy but rotten-tasting fruit, implying a yin and yang balance within fruit, as well as within humans. An accident with this process caused Lex to split into a good Lex and a bad Lex who referred to himself as "Alexander".

Silver kryptonite made an appearance in the fifth season episode entitled "Splinter'. Like the previous comics incarnation, this silver form was not a true form of the stone. In the episode, Clark pricked his finger on a rock that was black and had silver-metallic clusters, and subsequently became increasingly paranoid, hallucinating that others were conspiring against him. In the episode's final scenes, it was revealed that a splinter of the element entered Clark's bloodstream. It was also shown that silver kryptonite was created artificially from the liquid metal which forms Brainiac's body.

In the eighth episode of Smallville's 7th Season, entitled "Blue," there was a new form of Kryptonite. It was blue kryptonite, and it stripped Clark of his powers. This happened when Lara-El, Clark's mother, gave Clark his father's blue ring to wear, without knowing the effect it would have on him. The ring was impossible to remove until Clark returned to The Fortress of Solitude. As in the comics, blue kryptonite is fatal to Bizarro. It increases Bizarro's power exponentially so that his body is not able to contain it, causing him to explode.

Animated Series

Super Friends

The 1970s and 1980s Super Friends animated series featured kryptonite in various episodes. In the episode "Rest in Peace", Sinestro refers to a form of kryptonite called "Krypton Steel" as "a harmless form of kryptonite that only Superman can penetrate". In another episode, "Darkseid's Golden Trap", gold kryptonite appears, which is stated to have an effective range of 20 ft (6.1 m). Blue kryptonite also makes an appearance in an episode entitled "Terror From the Phantom Zone"; Superman, aging rapidly from exposure to Red Kryptonite, acquires a sample of Blue Kryptonite which had been discovered floating in space. Since Blue Kryptonite harms Bizarros, Superman reasons that it would help normal Kryptonians, and thus uses it to cure himself. In "Uncle Mxyzptlk", the Wonder Twins find a red, glowing stone and take it to the Hall of Justice. They show it to Superman, who immediately reacts to it. Samurai knocks the red kryptonite to the floor but the effects of the red kryptonite cause Superman to decrease in age, becoming a young child. The rest of the Superfriends refer to the kid as 'Super Brat'. In another episode, red kryptonite is exposed to Superman by Bizarro himself, causing Superman to transform into a gangly, weak klutz. In yet another episode, red kryptonite causes Superman to grow additional arms and legs. Most of the action takes place at the Fortress of Solitude where Superman finds some blue kryptonite hidden away to fight off Bizarro.

DC Animated Universe

In the 1990s series, Superman: The Animated Series, one explanation offered for the science of kryptonite is that Superman feels the detrimental effects of kryptonite radiation quicker than normal humans because his body absorbs it more readily, as a result of sharing a common point of origin with the element. The effect is so potent that even a tiny shard is enough to painfully affect Superman at a short distance. This makes it impossible for Superman to even touch the substance, as it would be the equivalent of a normal man touching radioactive rods from a nuclear reactor with his bare skin. Only the element lead can block the radiation, and it is therefore Superman's only protection. Fortunately, Professor Hamilton supplies Superman with a distinctive and durable lead protection suit for such situations.

Kryptonite, in the animated series, still has effects on normal humans as well. Two moments are evidence of this. First, the "Jade Dragon" from The Batman/Superman Movie (a crossover between The New Batman Adventures and Superman: The Animated Series) is a statue of kryptonite carved in the form of a Chinese dragon, said to be cursed because all of its owners all died within a few years of acquiring the piece. Second is Lex Luthor's kryptonite poisoning/cancer as seen in Justice League, attributed to Lex's admitted habit of keeping a fist-sized chunk of kryptonite in his pocket for years. This does bring up the question of Batman's habit of also carrying a piece of kryptonite in his own belt; however, since Batman has seen what the kryptonite did to Luthor, the famed methodicality of Batman may mean that he likely has the pouch lined with lead. In Batman Beyond, it was revealed in the two part episode "The Call" that Bruce Wayne kept the kryptonite for the rest of his life, and kept the needle of kryptonite locked up very securely in the Bat Cave. The Justice League series also reveals how Batman obtained the kryptonite.

Green kryptonite remains the only variety of the substance ever seen in the DC Animated Universe.

Krypto the Superdog

As mentioned above, the Krypto the Superdog episode "Streaky's Cat Tail" features "purple-spotted kryptonite", which causes Superdog to compulsively chase his tail. However, this was almost certainly a product of Streaky's imagination. Red Kryptonite has appeared and is stated as having weird effects on Kryptonians for a day; it has swapped the minds of Kevin and Krypto, removed Krypto's powers, and in another episode caused Krypto's tail to become sentient and separated from his body.

Legion of Super Heroes

Kryptonite also appears in an episode of the Legion of Super Heroes cartoon, where it is revealed Brainiac 5 has a piece of it, and that the villain Drax, who, despite being an analogue to Superman, is immune to it.