Pulverizer Returns!.Splinter has the Turtles switch weapons (Leo gets Donnie's bo staff, Donnie gets Raph's sai, Raph gets Mikey's nunchucks and Mikey gets Leo's swords) and having them use whatever is nearby as makeshift weapons in combat. Meanwhile, Shredder learns about the mutagen from the captive Kraang operative where he states that the mutagen has unpredictable results. When Shredder plans to create an army of mutants, the Turtles must rely on the help of the Pulverizer (who was recruited into the Foot) who volunteers to gather information on the inside on their behalf. When he carelessly agrees to be a test subject for a stolen supply of mutagen, the Turtles attempt to rescue him.