In "Legend of the Kuro Kabuto," Stockman participated in the massive hunt to retrieve Shredder's stolen helmet. During the fight with the Turtles over it, he accidentally kicked Fishface, who then called him Buzzkill, which Michelangelo remarked as what he should have dubbed the mutated Stockman. In "Vengeance is Mine," he created a batch of mutagen meant to mutate the Turtles into serpents and mindlessly eat Splinter, though that did not go as the Shredder planned because Karai (who was being used as the bait) got mutated instead, and the following fight ended up destroying his lab.