Mutagen, a glowing, green substance, that is located inside Baxter Stockman's Lab. This tank is used so that Baxter can create his own mutants. Mutagen Tank debuts in Mikey Gets Shellacne.
Ever since Baxter Stockman left the Foot Clan, he wanted to do something more. He decided to create his own mutant army to command. So he added a Mutagen Tank to his lab.