Yellow Egg

A Yellow Egg is a type of Yoshi Egg first found in Super Mario World

Super Mario World
In Super Mario World, Yellow Eggs are found in ? Blocks just like green eggs. After showing up, a Yellow Egg merely hatches into a yellow Baby Yoshi.

Yoshi franchise
Starting with Super Mario World 2: Yoshi's Island, Yellow Eggs are used as throwable objects. When a Yellow Egg hits an enemy, it drops one coin. Yellow Eggs can be acquired if Yoshi throws a green Yoshi Egg that recoils once from the wall, then catches it; if the Yellow Egg recoils once more, it turns red. Yellow Eggs can also be obtained from yellow Egg Blocks, though unlike the green Egg Block, Yoshi only gets one egg.