I'm thinking between Deadpool, Doomsday, or Lobo. All of em seem to be immortal for one so each can come back from virtually anything. They heal from death practically. I guess for best I would have to go with Lobo. He can heal himself to full from one little drop of his blood in no time while Deadpool is a huge Deathstroke rip off(irrelevant but true!).
Lobo wins.
Originally posted by HaSon
Not even a mention of the Manhunter from Mars?
The thing about J'onn is his shapeshifting lets him perform major feats, but it's only when he's conscious and directing it. He could regrow from his arm because he shifting his mind to it, but if he wasn't consciously directing healing, he wouldn't regrow a lost arm or a stab to the heart, let alone an entire body.