The Black hole generator is a device that would have appeared in the unfinished second season Rise of the TMNT episode Wedding Crashers. It was a wedding gift to Ghostbear and Ghostpepper, and in the episode, Raphael and Michelangelo infiltrated their wedding to retrieve it.
The Black hole generator was depicted as looking like a standard toaster. In Rise of the Teenage Mutant Ninja Turtles: The Movie, "Black hole toaster" is listed on a whiteboard as one of the methods April O'Neil tried to destroy the Krang keystone with.