In the Dungeons & Dragons fantasy role-playing game, creature types are rough categories of creatures which determine the way game mechanics affect the creature. In the 3rd edition, there are fifteen creature types. Creature type is determined by the designer of a monster, based upon its nature or physical attributes. The choice of type is important, as all creatures which have a given type will share certain characteristics (with some exceptions). In 3rd and 3.5 editions, type determines features such as hit dice, base attack bonus, saving throws, and skill points.
Certain magic items and special abilities, such as the ranger's favored enemy ability (prior to 4th edition) and bane weapons (in 3rd and 3.5 editions) interact with creature type.
An aberration can have a bizarre anatomy, strange abilities, alien mindset, or any combination thereof. Examples include the beholder, illithid (mind flayer) and rust monster. All aberrations have darkvision out to 60 feet. As a group, they have no other special abilities or immunities.
An animal is a living, nonhuman vertebrate creature, with no innate magical abilities or capacity for language or culture. Virtually all animals are based on real animals; creatures based on mythological animals are usually classified as magical beasts (see below). Besides ordinary fish, birds, reptiles and mammals, animals also include dire mammals and dinosaurs. An animal can never have an Intelligence score higher than 2 under normal rules; any animal that attains one becomes a magical beast.
Some real animals are rendered as vermin (see below) in D&D; this means they have no Intelligence scores at all.
A construct is either an animated object of some sort, or an artificially crafted creature. Most construct are mindless automatons, obeying their creator's commands absolutely. This makes them immune to bribery and absolutely trustworthy, although some take their orders literally and fail to consider their intent. A few constructs, however, such as Inevitables, are as intelligent as living creatures.
As they lack a metabolism or internal organs, constructs are immune to many effects, such as poison, fatigue, exhaustion, disease, ability drain, level drain, death effects and critical hits.
Constructs are almost always created by wizards, sorcerers or clerics, though some are created by other character classes or spell-casting monsters. The first step in making a construct, sometimes performed by a non-spellcaster, is building the body; the second is a ritual requiring the casting of specific spells to bind a spirit of some kind (typically an elemental drawn from the Inner Planes) into the body and imbue it motion and special abilities. Most constructs are made of metal, but other materials — including bone and corpses — can be used.
The creation methods for certain constructs are unknown, or might have much more stringent requirements. Warforged, for example, can only be created with the help of specific artifacts, the creation forges.
Golems are the best-known type of construct.
A dragon is a reptile-like creature, usually winged, and tends to have magical or unusual abilities.
An elemental is composed of one of the four classical elementals of air, earth, fire, or water. Elementals almost always have the extraplanar subtype.
A fey is a creature which usually has supernatural abilities and a human-shaped form. A fey also usually connected to nature, or some other force or place. Many are based on faeries from mythology. Fey share a common native language called Sylvan. The six fey from the 3.5 Edition Monster Manual are: Dryad: The dryad is a tree-spirit with the form of a beautiful female humanoid. A dryad who leaves the vicinity of her tree for too long dies. Grig: A tiny creature with the lower body of a cricket and the upper body of a miniature humanoid. Grigs are mischievous and lighthearted, and can play a tune on their fiddles that causes other creatures to dance uncontrollably. Nixie: A water-spirit with green skin and webbed appendages. It can charm other creatures to become its friends. Nixies are guardians of freshwater pools and streams and are most commonly found alone. They love music and make instruments from reeds on the banks of streams. Occasionally a nixie will lure a human into the water, but they are usually more interested in company rather than drowning a visitor. Nymph: A creature of unearthly beauty, with the form of a female humanoid. A creature who sees her may become permanently blind. Pixie: A small, winged creature with a knack for pranks and mischief. Pixies can become invisible at will, and carry special arrows that can put victims to sleep or cause amnesia. They are commonly found in groups of 3 to 5, but sometimes can be found alone. Pixies are particularly known for knotting hair, leading people astray, and pinching skin black and blue. Satyr: A hedonistic creature that frolics in the wild places of the world. It has the hind legs of a goat and horns on its head but otherwise looks human. It can play magical tunes on its pan pipes that cause varying effects of its choice.
Dwarves have a bonus to their armor class against attacks from creatures of the giant type, due to their experience with fighting these oversized foes.
Humanoids are bipeds of Small or Medium size with few or no supernatural or extraordinary abilities. Most humanoids can speak, and usually have well-developed societies. Larger bipeds are giants (see above), and bipeds with more special abilities are fey, monstrous humanoids or outsiders. In 3.0 and 3.5 editions, the Player's Handbook races (humans, dwarves, elves, gnomes, halflings, half-elves, half-orcs) are all humanoids.
Prior to 3rd edition, humanoid referred exclusively to orcs, goblinoids and similar creatures, while more advanced creatures such as Elves and Dwarves were referred to as demihumans and humans were outside of both categories.
A magical beast is similar to an animal in many ways, but usually has a higher intelligence, and possesses supernatural or extraordinary abilities. Examples include manticores and pegasi. All magical beasts have darkvision out to 60 feet as well as low-light vision; as a group, they have no other special abilities or immunities.
An ooze is an amorphous or mutable creature without a single solid form. Oozes are usually mindless and homogeneous, and reproduce by simply splitting into two. The most famous ooze is the gelatinous cube. Many oozes dwell underground, and most secrete an acid from their skin that dissolves flesh and other materials rapidly. Oozes are essentially blind, but an ability called "blindsight", which allows them to discern nearby objects and creatures without needing to see them, more than compensates for this.
An outsider is at least partially composed of the essence (if not the material) of a plane other than the Material Plane. Most outsiders (including angels, demons and devils) have the extraplanar subtype and live on an Outer Plane; the rest (such as aasimars, tieflings and couatls) have the native subtype and live on the Prime Material Plane. All outsiders have darkvision out to 60 feet. As a group, they have no other special abilities or immunities.
Planetouched are mortal creatures whose ancestors were extraplanar creatures such as celestials, fiends, or elementals. Aasimar (humans with celestial blood), tieflings (humans with fiendish blood) and genasi (humans with elemental blood) are the primary planetouched races. Other examples include tanarukk (orcs descended from demons) and celadrin (elves descended from celestials).
A plant is a vegetable creature that can perceive and affect the world in some way. Ordinary plants are considered objects rather than creatures.
Shapechanger was a type in 3rd edition. It was converted to a subtype in 3.5 edition.
An undead is a once-living creature animated by spiritual or supernatural forces. Some, such as ghosts and vampires, have Intelligence scores; others, such as zombies, do not. All undead have darkvision out to 60 feet and immunity to mind-affecting effects, poison, sleep effects, paralysis, stunning, disease, death effects, critical hits, nonlethal damage, ability drain, or energy drain. In general, cleric spells that heal other creatures damage undead, and vice-versa. Most undead can be "turned" (destroyed or driven away) by a Cleric.
A vermin can be an insect, arachnid, arthropod, worm, or other invertebrate. Some have magical abilities, and others are giant versions of real insects. Most vermin are considered mindless individually. Since many vermin are too small to model individually, they are often represented as swarms (clusters that act like single creatures and sometimes have hive minds).