? Bubble

"Throw eggs to break the ? Bubbles."

- Message Block ? Bubbles, also called Mystery Balls, or Question Mark Balloons  are objects that are found in Yoshi's Story, acting as a counterpart to the Winged Clouds from Super Mario World 2: Yoshi's Island. Like with ordinary bubbles, a Yoshi can pop a ? Bubble by simply throwing an egg at it or by touching it about 15 to 30 times. When the Yoshi bumps into it once, it simply gets knocked around, without popping. ? Bubbles occasionally just float or move around the area of the level above the ground. They can hide walking coins, a Shy Guy, a melon in a parachute, a Surprise Ball, a Heart Fruit, a White Shy Guy, a key, a Miss Warp, or a Balloon Bully.