You know, I once read what an author said, "You never kill a good villain without leaving sucessors." While it's likely that Gravity Falls won't return, I believe most good triumph stories must leave some sort of reminder that there is evil in the world and while the current job is done, there is more behind the corner, but that's another story (for fanfic and fanart).

Mudkip is an axolotl. Looks like Hoenn's water starter will be coming to Gravity Falls soon.