My favorite "Superhero" type character is actually more of an anti-hero type character. His name is Croyd Crenson, but he is more commonly known as "The Sleeper" because of his abilities. Croyd is from the Wild Cards series of novels by George R. R. Martin and Minlida M. Snodgrass. He featured in the very first book as a 14-year old boy who becomes infected with the wild card virus and has gone on to appear in many of the other books in the series.

What makes Croyd such a compelling character to me is the virus gave him very unique powers. His initial transformation gave him the body of an adult along with the ability to turn invisible. Unfortunately for Croyd, he would go into a deep coma-like sleep when he becomes too tired and when he wakes up it is in a new body with new powers. Sometimes the new body has awesome new powers, but sometimes Croyd will wake up with a "Joker" body instead. Because he has no control over these transformations, Croyd developes a phobia of sleeping as he never knows if he will wake up horribly deformed and stay that way, or worse, draw the "Black Queen" and die because of the transformation. This results in a amphetamine addiction in an effort to stay away for longer.

Croyd developes quite a reputation over the course of the books as nobody knows what he looks like after each transformation. He's also not a "do-gooder" like some of the other Aces in the book and isn't afraid to sell his services to the highest bidders. One of the most memorable books in the series is Wild Cards Volume III: Jokers Wild where Croyd wakes up as an albino Joker with the ability to spread the wild card virus to other people. This causes quite a stir as people become deathly afraid of him and he earns the nickname "Typhoid Croyd."

Some readers might consider Croyd to be more of a villian than a superhero because of his unscrupulous morals, but if you read the whole series you'll find that he is actually a very decent person. Anyway, hope that answers your question and interests you enough to check out what I think is a very underrated series of books that has been written by a wide range of authors. The author who created Croyd is actually Roger Zelazny, and I'm a bit bummed out that he passed away before he could get to the other Croyd stories that he wanted to tell.