Dark Beast (Henry Philip McCoy), sometimes known as the Black Beast, is a Marvel Comics supervillain, an alternate reality evil version of the X-Men’s Beast. Created by Scott Lobdell and Roger Cruz, he first appeared in X-Men: Alpha (1995).
In the Age of Apocalypse reality, McCoy was a nefarious geneticist who implemented cruel experiments under the tyrant Apocalypse. He was one of a handful of characters to escape the Age of Apocalypse reality to the regular Marvel Universe, where he has continued his unethical experiments.
Besides being one of the creators of the Infinites, the Dark Beast also experimented on Blink, on Jamie Madrox (thus being one of the creators of The Madri), merged all of the Power siblings into one hideous creature, made Nemesis into Holocaust following his defeat at the hands of Magneto, and was also responsible for the creation of Holocaust's lead hunter Wolverine (not to be confused with the Wolverine of the X-Men, who was known only as Weapon X in that reality).
With the end of the Age of Apocalypse, the Dark Beast was able to escape into Earth-616 through the M'Kraan Crystal. He was believed to have died due to Quicksilver's interference in his set trajectory. However, the only damage was that he landed twenty years in the past in the Morlock Tunnels. Upon his arrival he was met by a young Emma Frost, who helped him to regain some of his scattered memories. The Dark Beast was responsible for the creation of the Morlocks.
The Dark Beast later kidnapped the real Beast and kept him a prisoner behind a brick wall. He infiltrated the X-Men in his place by altering his appearance to match the real McCoy's fur color. He helped keep up the ruse by slaying many of Hank's childhood friends and teachers, although he found himself unable to kill Hank's parents. Angered at this emotional weakness, he decapitated a pedestrian as he left town. The Dark Beast was able to keep up his ruse until the Onslaught Saga, during which the Dark Beast joined Onslaught.
He also had a few run-ins with Generation X and Gene Nation. There he was the leader of the newly revamped Gene Nation, although through the robotic body of Wynter, attempting to capture Generation X in order to experiment on them. The previous meeting between him and Emma Frost was also revealed. He led an incarnation of the Brotherhood of Mutants and was revealed to have created the Morlocks, which would later be revealed as the cause for the Mutant Massacre.
Dark Beast returns and finally confronts his counterpart in the Endangered Species storyline where he ambushes him in Neverland, the extermination camp ran by Weapon X, to offer his services regarding finding a cure for M-Day. The two form an uneasy alliance to tackle the impending mutant extinction but part ways due to their drastically different moral approaches to science. During a trip to the Guthrie household aimed at requesting samples of DNA from the mother and father of several mutant, and non-mutant, children - the Dark Beast (without warning Henry) poisons one of the un-mutated Guthrie boys in a quick scientific experiment. He then carries the dying boy's body back to the house, suggesting that they should try one of the girls next. Shocked and enraged with his actions, Hank attacks the Dark Beast who, disgusted with Henry's inability to do all that is necessary to save their mutant species, beats him almost unconscious. The fight is interrupted by Mrs. Guthrie, who fires a round from a double-barrled shotgun into Dark Beast's left shoulder. After scolding Mrs. Guthrie for thinking a round of birdshot would put him down, the Dark Beast is knocked unconscious by Henry.
While as intelligent as his counter-part, "normal" Beast seems to possess a larger spectrum of knowledge, as evidenced when Dark Beast was infiltrating the X-Men, he became annoyed at the amount of knowledge the X-Men expected him to possess. This is due to Dark Beast specialising in genetics, while 616 Beast maintained study in multiple fields.