Robobird

Robo Birds (ロボバード, Robo Bādo) are mechanical airborne enemies in Wario Land 4. They are blue-gray and have a drill for a beak. They only appear in the Hard and S-Hard modes of the game, in Ruby Passage levels.

Robo Birds use a jetpack to fly. They are intially found flying in one spot in mid-air. When Wario draws near, they charge in a straight line towards him. They can pass through walls and hurt Wario if they touch him. Robo Birds can be defeated with a jump attack, a ground pound or by throwing something at them, but will not yield any coins. Unlike most enemies, Robo Birds can respawn in the same map Wario is on (compared to most support enemies which would only respawn if Wario leaves the area first).