Source: marvel.wikia.com
7. Mimic
AKA Calvin Rankin
Joined: X-Men (1963) # 27
And here’s where we start getting to the weird ones. Calvin Rankin AKA Mimic was the first non-original mutant recruited to the X-Men, even if he didn’t last too long. His powers allowed him to mimic the unique abilities of anyone within a certain (poorly defined) radius of him.
After fighting the X-Men and then apologizing, Mimic would get his shot on the team when Jean Grey had to temporarily leave the Xavier School. Dude even made Deputy Leader. Unfortunately, he wasn’t patient enough or humble enough for the X-Men and lost his powers in a fight. He’d regain them and spend a few decades as a villain again.
Even serving on Norman Osborn’s Dark X-Men trial team until HAMMER totally fell apart. The X-Men tried to recruit him again but he and his Dark X-Men buddy Weapon Omega were just done with being X-Men.
