Petbottom

A PET Bottom is one of the many enemies that appear in the Game Boy Advance game, Wario Land 4. They only appear in the Ruby Passage, and resemble a bottle full of a pink liquid, which has a sharp spear attached to the front of the cap. They have legs, and they walk back and forth. The only threatening part of a PET Bottom is the spear.

Wario can defeat a PET Bottom by either ground pounding the top side of the enemy, body slamming the non-sharp side, or by doing a super ground pound nearby; the PET Bottom will flip upside down and Wario can attack the underside.

Trivia
Even though the "PET" part of the word PET Bottom is in capitals, it doesn't seem to stand for anything.