Tap-Tap the Golden
From the Super Mario Wiki
Tap-Tap the Golden is a giant golden invincible Tap-Tap found in Door Three of Baby Bowser's castle in the game Super Mario World 2: Yoshi's Island. The screen slowly moves through a lava-filled cave as Tap-Tap the Golden chases after Yoshi. It can be hit into the bottomless pits, but it will only come back. Knocking it off of the screen is the best option, and several Fangs are around to supply Yoshi with eggs for repetition of this strategy. The mini-boss is invincible in normal gameplay, but can be defeated through hacking.