In the alternate dimension he came from, Hank McCoy was a mad scientist working for Mister Sinister in his breeding pens, intent on breeding more powerful mutants according to Apocalypse's "survival of the fittest" dogma. However, while Sinister was methodical and rational in his experiments, McCoy (as ruthless as his mentor) sadistically delighted in causing pain to his lab subjects and in the cruelty of his experiments, which is why he was nicknamed the Beast both by prisoners and Sinister's Elite Mutant Force. McCoy also experimented on himself in order to further his mutation, and gained his ape-like bestial appearance. Any mutant that he deemed unworthy was turned into a component of a genetic stew that was used to create Apocalypse's army of Infinites.

Added some wild hairs and then a complete repaint. Comments and suggestions welcomed!
Thanks
Lee