Reo are small, fly-like creatures that are native to Zebes. They live in the caverns of Brinstar, and will dive at any creature it spots. On the Bottle Ship, they are seen coming out of nests of biomass. Whether this is part of their natural life cycle or a mutation caused by the Galactic Federation is unknown. Also in Other M, the Reo are capable of gripping on to Samus, forcing her to shake them off. The X Parasite mimicked Reos on the B.S.L station, they act the same as in previous appearances. They are generally enemies of low threat, but can be dangerous in groups.
