From the Super Mario Wiki
The three size variations of Pwallop.
Pwallops are blue variations of the Protobatter that Mario and Luigi encounter inside Bowser's body in Mario & Luigi: Bowser's Inside Story. They are found in the Energy Hold. They can vary in size just like their weaker counterparts and have the ability to produce shock waves with their club. They can also spit out yellow balls that they use to whack at either Mario or Luigi. However, Pwallops can sometimes miss the balls when they swing their club. When Mario or Luigi attacks a Pwallop, it grows either one or two times its size.
Names in other languages
|Seems to be derived from "Polyp", a type of medical condition.
||From Pólipo, meaning Polyp.