McCoy's mutant body is large, muscular, and gangly, with oversized limbs, hands and feet. Hence the code name "Beast". In McCoy's case the term superhuman entails strength several times greater than the strongest olympic wieght lifter who has ever competed, and faster reaction time and agility than is humanly possible. The Beast can lift more than a ton (2000 lbs.) without really exerting himself, standing jump the distance of a football field, run faster than 30 miles an hour, and play tennis (or knit a sweater) with his feet.
Despite his appearance and physical skills, McCoy is also highly intelligent and a trained scientist, with a large vocabulary which he often uses to enhance his sense of humor.
Henry McCoy's mutation manifested itself in his adolescence and although he used his powers to accell in athletics for a time he was quickly forced to seek refuge from the inevitable ostracism and irrational hostility of normal humans. He was approached by Professor Charles Xavier who knew of his mutant powers. He was given the option of joining the "Manchester School for Gifted Youngsters", which was actually a front for the benevolent instruction of mutants like himself. He joined the school and the X-Men, where he was given the code-name: The Beast.
Some years later (in Amazing Adventures #11), McCoy left the X-Men and became a research scientist. He attempted to develop a therapy to reduce the freakish aspects of his appearance, but it instead mutated him further, as he grew gray fur all over his body (which later turned blue), as well as elongated canine teeth and enhanced senses. Despite this, McCoy is one of the most upbeat and cheerful of superheroes, although at times acting the role of the "class clown".
Not long after this, he was recruited to join The Avengers, where he remained a member for many years, becoming a close friend of Wonder Man. When the original X-Men formed X-Factor, McCoy left active service in The Avengers and joined that team, later returning to the X-Men, where he remains.
The Beast is occasionally confused with another X-Man, Wolverine, though temperamentally the two are quite different. Hank McCoy also has an evil doppelganger known as the Black Beast who escaped from an alternate dimension. The Black Beast has all of the powers and intelligence of Hank McCoy.