Gruzzer

Behaviour and Tactics
Flies around, bumping into walls and objects, changing direction on contact.

It's best to follow behind it then strike it down.

Locations
LOCATION IMAGES MISSING

Trivia
On the official website, it is referred to as "Droobling Muzznik":

"These morose-looking flies buzz around haphazardly through the caverns, bouncing off of walls and irritating travellers."

Граззер