Bug-Eaten

Bug Eat and an unnamned rat are two stand-using brown rats from Part IV: Diamond is Unbreakable. While without evil intent, the two rats bear natural instincts of eating and go after even humans as a food source.

Synopsis
While Akira Otoishi had Keicho Nijimura's Arrow in his possession, he tests out its powers by using it on some rats to test it out. The arrow pierces two rats, granting them both the stand Ratt. The rats are later hunted by Jotaro Kujo and Josuke Higashikata for damage control after Jotaro questions the defeated Akira. In the process, the two rats had managed to meld together the bodies of other rats into cubes of flesh, and were in the process of testing out their ability on humans as well.

Trivia

 * "Bug Eat" is a name given by Jotaro, referring to the hole in its ear. An English equivalent could be something along the lines of "Mothy".
 * The hole in its ear is likely a wound from the Arrow, making both rats stand users.