A group of Brugs and one Emperor Brug were bred on the BOTTLE SHIP, possibly for scientific purposes. Before entering the BOTTLE SHIP Control Room, Brugs can be seen crawling around in certain rooms. Such rooms include one with a Kick Climb shaft and the room directly outside the control room.
While Samus and the 07th Platoon were exploring the area, they encountered the swarm in the Control Room, which created a Brug Mass. Through the use of Samus's Missiles and the Platoon's Freeze Guns, the Mass became incapacitated and the Emperor was destroyed.
After the fight, when Samus Aran exits back through the preceding corridor, some Brugs will scurry off into the vents. These remaining Brugs are not seen again through the remainder of the game.
- Zebesian parasites seem similar to Brugs and may or may not represent the first depiction of the species.
- The name 'brug' seems to be derived from 'bug', which is a generic name for insects like the Brugs.