Parasitica.While investigating a destroyed Kraang hideout, the Turtles are attacked by a giant mutant wasp, which stings Leo. After the wasp dies they find an egg, which Leo says should be brought back to the lair. That night, Raph tries to destroy the egg but Leo, who is under the influence of the wasp's toxin, is determined to protect the egg. Leo bites Raph, infecting him as well. Mikey and Donnie attempt to cure them, although Donnie gets infected before he can finish the antidote. Donnie instructs Mikey on how to prepare the cure before succumbing to the infection and biting him. Mikey knocks him out, then finishes the antidote while desperately fighting off the influence of the bite, and administers the cure to himself and his brothers just as the egg hatches. Mikey then kills the newborn wasps with the Shellraiser's cannon.