Boo Balloon

A Boo Balloon is a Boo in the shape of a blue balloon in Super Mario World 2: Yoshi's Island. They race about the screen, trying to deal damage to Yoshi. They will inflate when hit with an egg. After three hits, they will explode, yielding coins or sometimes a ! Switch. They appear in Bigger Boo's Fort and Don't Look Back!, with the former called Blue Boos in the Nintendo Power SNES guide due to the black background rendering the string invisible.