A frizz-rat is a Cybertronian lifeform that gnaws holes through stuff.

Fiction

Wings Universe

The rust eating through the metal of Median was compared to an oversized frizz-rat. Flames of Yesterday

Beast Wars: Uprising

Some frizz-rats had nibbled at the acid-resistant coating of the Melpomene Bridge, exposing it to more damage from acid rain. Burning Bridges