Source: marvel.com

7. The Beast

Hank McCoy is pretty goshdarn smart.

In fact, he's pretty much the poster boy for smart X-Men. I mean, yeah, Professor X is pretty smart, but he's telepathic, and that's just cheating. McCoy got smart through study and hard work. Born and raised in Illinois, Hank grew up with his mutation of very large hands and feet that gave him slightly enhanced strength and VERY enhanced agility. These powers made him an all state football star. But he was also brilliant.

Hank loved studying as much as he loved sports. Find another mutant who can do both. But Hank eventually was found by Professor Charles Xavier, and was inducted into the X-Men, where he'd become a part of the famous First Class. He nursed a crush for Jean Grey for some time, but moved on around the time he made what can only be described as a horrible mistake. You see, Hank started experimenting with the gene that creates mutations. It…uh…it turned him into a monster. Like a blue wolfman? But more catlike?

Horrifying. But also horrifyingly smart.