Bummie? Bummy? - species names are always singular
Talk about it here.
The Bummies were a race of monsters brought into a desolate wilderness by PAND-R in order to fight Iris Wildthyme. After defeating the Chumbloids, various other creatures and PAND-R in the tower, Iris claimed that it was lucky only the "rubbish monsters" had been pooper scoopered to the wilderness. (PROSE: From Wildthyme with Love)