Nano-flea

A nano-flea is a Cybertronian lifeform, presumably similar to normal fleas.

Fiction

3H comics

According to Optimus Primal, Tigerhawk had nano-fleas, and they had more integrity than Razorclaw. Escape

Animated

Beachcomber once found a whole colony of nano-fleas living in one of his tires. While most people would probably be bothered by something like that, he was pretty cool with it. The AllSpark Almanac II