Skonk was the leader of the terrorist organization Humans Against The Extraterrestrials ("H.A.T.E.") in the episode H.A.T.E. Due to the recent invasion by the Triceratons, Skonk and his organization were determined to dispose of perceived lingering alien threats. To this end, he had obtained a thermonuclear bomb, and was planning to detonate it in the middle of New York City.
The Turtles first encountered Skonk when he was chasing a rogue member of H.A.T.E. through the woods, after which he gave a motivating speech to his followers. His operation was disrupted when Donatello and Raphael sent vehicles and weapons crashing into the H.A.T.E. base, and he caught the two Turtles as they discovered the nuclear bomb. They disarmed him, but he pepper-sprayed them and drove away with the bomb.
His attempts to evade them failed, as Donatello was able to enter the trailer to disarm the bomb while Raphael invaded the cab of the truck. He fought Raphael and was knocked unconscious; the Turtle then extracted Skonk from the truck when the detonating charge of the bomb was set off. Skonk was then left for the authorities with the removed plutonium core of the bomb.