Marvin is a mammoth and was a member of Tonka's wrecking crew. Teggs and Iggy first met Marvin and a friend when Tonka took them to the engine room in The Planet of Peril. Tonka asked them if they did "the job", and they said yes. This "job" was secretly hiding a gravel grenade in the room to scuttle the DSS Sauropod on Aggadon. During Tonka's conversation with Teggs and Iggy, Marvin mentioned the incredible value of slodge to Tonka and his team, revealing that he was just as money-grubbing and unscrupulous as his boss. He later said that the mammoths would kill the Sauropod crew so that they couldn't mess with their profits, because Teggs and Iggy knew too much about their plan to steal all of Aggadon's slodge by destroying the planet. Sprite and the dimorphodon interrupted, helping Teggs drive the mammoths out of the ship. The fate of Marvin is unknown, but he presumably went to jail with Tonka.
- In The Dreams of Dread, a flock of flying mini-mammoths appear, having been dreamt up by one of the crew. These mammoths could have been from the memory of Marvin and Tonka.