Brug

Brugs are small, purple insects which appear in Metroid: Other M. Although Brugs do not seem to have any offensive capabilities on their own, when a large group of Brugs joins together under an Emperor Brug, they can form a Brug Mass to attack.

A group of Brugs and one Emperor Brug were bred on the Bottle Ship, possibly for scientific purposes. While Samus Aran and the 07th Platoon were exploring the area, they encountered the swarm, which created a Brug Mass. Through the use of Samus's Missiles and the Platoon's Freeze Guns, the Mass was incapacitated and destroyed.

Etymology
The name 'brug' seems to come from 'bug', which is a generic name for insects like the Brugs.