Russell "Russ" Gregory (2012 TV series)

Jake is a bounty hunter. After coming face-to-face with the Kraang, he came into contact with mutagen, transforming him into an anthropomorphic kangaroo, which Michelangelo dubbed "Walkabout". He was later payed by the Shredder to hunt down Splinter and the Turtles, but became their ally after Raphael saves him from the Kraang.