Egg Throw (たまご投げ, Egg Throw) is Yoshi's up special move. When used, Yoshi launches an egg upwards in an arc, which can be angled along a variety of trajectories, hitting anywhere from far horizontally in front of Yoshi to slightly behind and above Yoshi.
The trajectory of the egg can be controlled by where the control stick is tilted while Yoshi is in the throwing animation, and the distance can be controlled by how long the special button is held. The egg explodes upon contact or after moving along for a set air-time. Yoshi's up special is fairly unique in Super Smash Bros. and Super Smash Bros. Melee in that it is not a triple jump, does not noticeably aid in recovery, and does not put Yoshi into a state of helplessness.
However, it does help with recovery in Super Smash Bros. Brawl, Super Smash Bros. 4 and Super Smash Bros. Ultimate, while still not causing helplessness. Yoshi can use Egg Throw many times in the air, gaining some height each time; however, the height he gets decreases each time the player uses it in the air, and he will continue to lose height until the move gives no height at all. Also, the Egg Throw's versatility was dampened substantially in Brawl by the fact that Yoshi is now forced to choose between certain egg "routes", as opposed to before when the eggs could end up anywhere. Additionally, it's possible for the egg's explosion to miss, even after the egg hitbox hits its target. In SSB4 and Ultimate, the egg throw makes a rainbow trail.
In Super Smash Bros. Ultimate, the eggs from Egg Throw now bounce on the ground.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
Starting in Super Mario World 2: Yoshi's Island, Yoshi would eat enemies to turn them into eggs and then aim and throw the eggs at other enemies. The eggs would fly straight, bouncing off walls and skimming across water. In Yoshi's Story, eggs stopped bouncing and instead exploded upon reaching the point of the aiming cursor; the size of the explosion was based on the Yoshi's happiness and color. Yoshi can carry six eggs at a time, though objects such as keys count towards the six slots.
In the Smash Bros. series, thrown eggs arc due to gravity. The only time this occurs in a non-spinoff game is the final battle against Giant Baby Bowser in Super Mario World 2: Yoshi's Island, where Yoshi throws giant eggs into the background; in all other instances eggs fly in straight lines, ignoring gravity.
The rainbow trail used in SSB4 and Ultimate may be a reference to Yoshi's "Rainbow Swing" Star Swing in addition to his "Rainbow Ball" Star Pitch in Mario Super Sluggers, which both feature a similar rainbow trail.