Inside Baxter Stockman's Lab, Dogpound and Baxter Stockman were inside when Fishface came. He asks why he hasn't taken Stockman to Karai, which Dogpound replies that he will until Baxter cures him from his mutation. Lying to the two mutants that he will cure them, Dogpound placed a collar around his neck. But this collar contained Mutagen, making it the Mutagen Collar.
- Mikey Gets Shellacne (Debut)
- Wormquake! Part One
- Wormquake! Part Two
- The Lonely Mutation of Baxter Stockman (Last Appearance)
- In The Lonely Mutation of Baxter Stockman, the Mutagen Collar was the cause of the mutation of Baxter Stockman into Baxter Fly.
- In Mikey Gets Shellacne, Dogpound was the one who put the collar on Stockman.
- To activate the Mutagen Collar, there is a button that must be pressed.
- When the collar is activated, it acts like a bomb.