Krulik

Captain Kroolik is an alien circus owner (who appeared in "Back to the egg") who travels the galaxy along with his freak circus of intergalactic mutants. Krang made Back to the egg: Krang would turn the Turtles with a age-reversing serum that he made himself into toddlers, and while he and Shredder take over the city easily, Kroolik can keep the Turtles as a new part for his circus

Krang sent him and Shredder to Earth, but Shredder didn't like to work with Kroolik, especially when Krang has more faith in him than Shredder.