Piragilon

Piragilons (ピラギロン piragiron) are a piranha-like species of fish with incredibly strong jaws and teeth. As can be expected from creatures with those features, their voracity is not to be trifled with. Piragilons eat everything they can sink their teeth into, whether that be an organic or mechanical dish. Despite being fishes, piragilons can survive outside the water for a time, but their mobility becomes limited.

Fiction

The Headmasters cartoon

To protect the factory complex on planet Beast, the Decepticons set a school of piragilons free in a bog that hid one of the factories' entrances. When the Autobots agreed to help the Beastformers under command of White Leo free their comrades from enslavement in the complex, they asked for another way in than the heavily-guarded main gate and were told about the bog entrance and the piragilons. Platinum Tiger elaborated on the creatures' threat that if they'd be able to get in through the bog route, they'd be the first of many who've tried. Fortress had a solution though, and went to fetch Battleship Maximus, with which he sucked the bog empty of water. The piragilons were left lying around harmlessly, allowing the Beastformers to infiltrate the complex.

Some time later, the Decepticons showed up to defend the factory complex. After a long battle, Cyclonus, Scourge, and Galvatron were thrown into the piragilon pile. The fishes' attempt to eat the three Decepticons was the last incentive for them to retreat. Rebellion on Planet Beast