Henry McCoy (Earth-21399)

Early Life
Unlike most mutants, Henry Philip McCoy's powers manifested at birth, his unusual proportions causing his mother to suffer difficulties in childbirth. Although Hank's parents were remarkably supportive, Hank was relentlessly bullied in high school for his apelike appearance. As a result, Hank buried himself in his books, hoping to understand and potentially "fix" his mutation.

Further Mutation and the Xavier Institute
After completing his doctoral studies, McCoy found work as a genetecist at the pharmaceutical giant Brand Corporation, where he met Charles Xavier. Charles offered Hank the chance to work at his school and help him make a difference, but Hank refused.

Under the auspices of developing a hormone enhancement, Hank eventually managed to develop a serum that he believed could help him to control his mutation, giving him a "normal" appearance while leaving his powers intact. However, the serum instead had the opposite effect, further exaggerating his proportions and causing him to grow blue fur all over his body. Worst of all, Hank became consumed by bestial instincts and soon went on a rampage through the facility, becoming a wanted fugitive. The public came to believe that the “Beast” was responsible for Hank McCoy's death.

When Charles heard about Hank's sudden disappearance as well as the sightings of the Beast, he set out to investigate. He eventually discovered Hank hiding in an alley and telepathically brought him back to his senses. Hank was grateful for Charles' help, and seeing as how he now had nowhere else to turn, he accepted a job at Charles' school as a teacher. Under Charles's guidance, Hank eventually learned to accept his mutation and became a loyal ally of his, even creating the design specifications for the mutant-detecting device called Cerebro.

The X-Men
To be added...