Helipon

Helipon (ヘリポン) is an odd flying enemy in Mega Man 4 that was formerly a cave exploring robot. It was originally planned to hover in the air, but due to budget constraints, it ended up with a propeller. It spins around and floats down slowly. When Mega Man is close, it will drop down and start shooting. It appears in Drill Man's stage and Stage 4 of Dr. Cossack's castle.