Years active in the WWE: 1997-1999

At the age of 49, Ken Shamrock is gearing up to fight Ian Freeman in an MMA bout in England this July, his first organized fight in three years. He's drawn some criticism for fighting well past his prime. Dana White claims he would pay Shamrock not to fight because he fears serious injury will come to him in the ring. Shamrock shot back at White and accused White of taking advantage of fighters.

He's opened a school for "submission fighting" (martial arts) and has even trained marines. In his personal life he has an estranged relationship with his brother Frank (if that sounds familiar, it's because he's also a pro fighter) and has seven kids and three grandkids. Come to think of it, maybe grandads shouldn't be in the octagon. 

His son Ryan fought in his MMA debut in 2007 but also hasn't fought in three years; his son Sean made his debut in 2010 but got sidetracked when he lost a kidney due to kidney cancer.

Recently Shamrock's been under investigation for (allegedly) assaulting a woman at a mall in Modesto because he thought she was a man (which is not, like, as crazy an excuse as you might think). He also apparently popped her mom in the process.