From the Super Mario Wiki
Mario bowling over some Pinheads
Pinheads are a type of creature appearing in the game, Super Mario Galaxy 2. They appear as bowling pin-shaped enemies with two beady eyes, a red squiggly mouth, and a yellow antenna. These creatures are very rare, only appearing in two galaxies: Boulder Bowl Galaxy and Melty Monster Galaxy. They can only be defeated by Rock Mario, and when they see the plumber turning into a rolling boulder, they tremble desperately. But if Mario walks over to them, they hide in holes underneath themselves.
Names in other languages
||Portemanteau of birillo (pin) and spina (plug)