Tank-tanks were weapons used by the megalodon to attack the bactrosaurs, but were supplied to them by Janice and her terror bird allies. They were made of a container filled with water that contained one megalodon, which was inside with waterproof controls. Tank-tanks were armed with two cannons that shot blobs of dung at their targets. A golden tank-tank was used by their ruler, King Fin. The ones King Fin used, however, had been sabotaged by their makers and were intended to trap the megs and cook them.