Victor Falco (The Next Chapter)

The Rat King is was a creepy mutated rat man who lived in the sewers and developed a telekinetic bond with the sewer rats that live with him. He is voiced by Jeff Garlin.

History
Dr. Victor Falco was a scientist that worked with Baxter Stockman. Baxter Stockman performed experiments on Falco and transformed him into Rat King, mutating him with ooze that held rat DNA.

After Falco was mutated, he went to live in hiding underground in the sewers. Since Falco was now a rat, he had the power to speak with other rats. But Falco had special powers, he could control the minds of the rats. So, he used his telekinesis to become the Rat King.

Abilities
The Rat King has the ability to control rats telepathically, which allows him to direct them at his enemies. It is not explained why he has this power, but presumably it is related to his mutated rat DNA.