Robobird

Robo Birds (ロボバード, Robo Bādo) are enemies found in the Game Boy Advance game Wario Land 4. As their name imply, the species is a robotic bird. It only appears in the Hard and S-Hard modes of the game.

The Robo Bird is blue-gray and has a drill for a nose. They fly in a straight line (and even through walls) with its jet pack upon spotting Wario, and can only be defeated by a ground pound to the head by Wario. Unlike most enemies, Robo Birds can respawn in the same map Wario is on (compared to support enemies which Wario would have to leave the area first), making them tedious to deal with, as they're strategically placed around the rooms.

Robo Birds only appear in the Ruby Passage.