Stockman's big change occurred in the second-season episode, "Enter: The Fly", in which, after a failed attempt to generate a force field between the towers of the World Trade Center, the Shredder decided he required brawn to replace Stockman's brains. Instructing Krang to send his mutant flunkies Bebop and Rocksteady through a dimensional portal to Earth, the Shredder was warned that the dimensional interface was unstable, and required that someone be sent back through the portal to maintain the balance. Stockman was elected, and much to the scientist's horror, was hurled through the portal to Dimension X. Krang had no use for Stockman's scientific talents, and simply chose to kill him, tossing him in a disintegrator unit. However, in a reference to the 1986 movie "The Fly", a common housefly that had been on Stockman's clothes when he was tossed through the portal was also trapped in the chamber with him, and their molecules wound up being intermingled, cross-mutating Stockman into a giant, humanoid fly-creature. Immediately determined to get revenge for his mutation, Stockman fled Dimension X and attacked both the Turtles and the Shredder, but his addled, not-entirely-sane mind was open to suggestion, and the Shredder managed to talk him down by convincing him that the Turtles were responsible for his condition (ironically, the Turtles never recognized Stockman in his new state). Stockman then aided the Shredder in a plot to trap the Turtles a micro-second forward in time, forever out of phase with the rest of reality. During the battle that ensued, however, Stockman wound up accidentally flying between the two pylons of the device, and disappeared in a flash of energy.