Rat King is one of the most common foes of the Teenage Mutant Ninja Turtles, but each incarnation of him is wildly different from the other.

Splinter, Casey Jones, a Foot Clan Ninja, and the Shredder are here ... of Splinter back when he was a hyper-intelligent rat who had not yet been exposed to the mutagenic ooze, as well as the ...

Through contact with a mysterious ooze, four turtles in the sewers of New York mutate into intelligent pizza-loving humanoids, and are mentored in the art of ninja combat by the wise rat Splinter.