The Rat King, TMNT Wiki

The Rat King is a character and a villain in Teenage Mutant Ninja Turtles. He first appeared in the episode Monkey Brains. After his final fight with Splinter in which he falls off of a cliff, Falco is now deceased. "Formerly a scientist who studied DNA and parapsychology, I put one of my mutagenic hybrid compounds to the test, and accidentally transformed myself into the king of all rats. I now have the ability to command rodents, including Splinter. And I won’t rest until his meddlesome turtle

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