Zebesian parasites are a species of small creature native to Brinstar on Zebes in Metroid: Zero Mission. They attach to Samus Aran, causing a large amount of damage until she obtains the Varia Suit, which protects her from the damage. They are the only known creatures that can destroy a Zebesian Geron. They can only be destroyed with Bombs. Parasites are also immune to Lava and Acid, showing how potent creatures they are despite their small size. The creatures will detach themselves from a host if the victim leaves their native room.
The creatures highly resemble Brugs. However, it is currently unknown if the two species are the same or not.