Some TMNT stuff really isn't for little kids.
In the IDW continuity, Dopey first appears in Teenage Mutant Ninja Turtles issue #105, as a patron of the heavy metal nightclub named Kennel Klub. He was seen in the background alongside Scrag, Grunt and Dumbo when Bandit and Puggle confronted Jennika.
As a mutant, Dopey is a tall shrew mutant with pale brown fur. He wears a long dark gray coat and a distinctive light gray Fiddler cap.