Comic book fans tend to shudder at the thought of a heavy handed retcon. Spider-Man fans could certainly rattle off a few instances of retroactive continuity that have marred the character ("One More Day," "Sins Past," Aunt May's resurrection ...). But I like to be optimistic, so on ComicBook.com, I ranked five of the best retcons in comic book history. These are the moments that changed a series for the better.