The Bad Guys (book series)
Mr. Snake – a Eastern brown snake, who works on stealth tactics of the team. Being very self-centered and shady, he often diverts from the Good Guys Club's goals of being good by doing whatever he wants, and most of the time can't stay away from doing misdeeds, but he can be selfless when he wants to. During the second arc of the books, he is possessed by an otherworldly entity and becomes the antagonist known as "The Underlord".