Astro tick

An astro tick is, presumably, a form of Cybertronic wildlife.

Fiction

Generation 1

Ironhide once compared the local number of Decepticons to the density of astro ticks found on Ravage's aft portion. G.I. Joe vs. the Transformers

Ironhide's simile seems to indicate he believes Ravage is a dog. It's a common misconception.