Yoshi's Egg

In most games featuring Yoshis, Yoshi Eggs are involved. Yoshis are known for being capable of laying eggs at will, sometimes with Yoshis or items inside.

Super Mario World
When Mario or Luigi collect one of these in Super Mario World, a Yoshi hatches and they can ride it. On Yoshi, they can swallow enemies with the X or Y button. If Mario or Luigi get another Yoshi Egg and the one of the brothers have a Yoshi; a 1-Up Mushroom will pop out for a bonus for keeping the Yoshi. Mario will also rescue an egg from each Castle he encounters. These eggs do not hatch until the end of the game.

''Super Mario Bros. Deluxe
Yoshi Eggs also appeared in the challenge mode of Super Mario Bros. Deluxe. In challenge mode, the player must collect red coins or eggs. Red coins could be found normally, like regular coins, but Yoshi eggs are tougher to be found. Yoshi eggs may only be found from hidden blocks throughout the level. Collecting both in a certain amount of time will affect the score and if the player collected the eggs fast enough, he/she may earn a reward.

''Super Mario 64 DS
Though no Yoshi eggs appeared in Super Mario 64, they appeared in Super Mario 64 DS as a helpful projectile for Yoshi. They can be acquired by eating enemies and swallowing them to turn into Yoshi eggs. Unlike Yoshi's Island, Yoshi can only carry one egg at a time. If Yoshi wants to stick his tongue out again, he must throw his egg in order to eat again.Yoshi Eggs will home enemies in screen and can bounce off enemies to hit another. If Yoshi swallows a wooden crate, the egg will take in form as a crate.

Eggs also appeared in both of Luigi's minigames, the Mario Slot and the Super Mario slot. Among the other slots, a Yoshi Egg is in them. Getting three Yoshi Eggs in a row will earn the player 5 coins.

Super Mario World 2: Yoshi's Island
In Super Mario World 2: Yoshi's Island, Yoshis can lays eggs by swallowing enemies. Yoshis can also obtain these eggs by hitting a Egg Block that contains an unlimited supply of Yoshi eggs, the Yoshi can only carry 6 eggs. Eggs can also fall into Tulips in this game, resulting in the Tulip spitting out stars. There is the standard green egg, Yellow Eggs, Red Eggs, and Flashing Eggs. All of these eggs, except the green egg have a different effect.

Super Mario Sunshine
Yoshi Eggs appear in Super Mario Sunshine as well. Shadow Mario has one in Delfino Plaza and the player needs to stop him by spraying him with FLUDD. Then the player needs to get a fruit. A certain one needs to be acquired, and it will be the one in a small thought bubble over the egg. When the fruit is brought to the egg, a Yoshi will hatch from it. These eggs will then appear in many levels, and are sometimes needed to finish a level.

When Pinna Park was invaded by a Snooze-A-Koopa colony, the Yoshis residing there fled, insulted by the appearance of creatures who resembled Yoshi eggs. Completing the episode in Pinna Park will cause the Yoshi eggs to appear all over Isle Delfino.

''New Super Mario Bros. Wii
Yoshi returns in this game, hatching from a Yoshi egg when a player hits the block. The Yoshi egg acted in a similar manner in Super Mario World, which Yoshi also hatches from an egg that got spawned from a certain block. However, no Yoshi eggs could make 1-up Mushrooms. Instead, Mushrooms popped out of Yoshi Eggs.

''Super Mario Galaxy 2
A Yoshi Egg appears in Super Mario Galaxy 2, which Yoshi would come out of. Nothing else is known about other egg-related appearances, concerning this game.

Wario Series
The treasure for the third level "Invade Wario Castle" in Wario Land II resembles a Yoshi Egg.

Yoshi's Story
Yoshi eggs are laid automatically in Yoshi's Story, but are still used as projectile weapons. Unlike in Super Mario World 2, the eggs hold no special effects; although eggs thrown by the White and Black Yoshi have more of an explosive impact.

Yoshi's Island DS
Yoshi eggs act the same way in Yoshi's Island DS, there are also yellow eggs, which produce two coins if one hits an enemy or a cloud, and red eggs, which produce two stars. Flashing eggs make a cameo in Secret 5 as a tracker for which Easter Egg the player is on. but are not usable in the game (in the original Yoshi's Island, they provided a red coin.)

Yoshi Touch and Go
In Yoshi Touch and Go, Yoshi lays eggs when he collects fruit. The eggs can be used to collect items and defeat enemies.

Super Smash Bros. Series
These eggs can be used as a weapon in Super Smash Bros.. A single Yoshi Egg appears in one of the events of Super Smash Bros. Melee. In it, the player, as Yoshi, must keep the Yoshi Egg from breaking. If it is broken, the player fails. If time runs out and the Yoshi Egg isn't broken, the player wins.

''Super Mario Kart
An egg is used as a projectile as Yoshi in Super Mario Kart. Only the computer may use the egg and Yoshi has an unlimited supply of it. The egg is like a "special" item that most of them are exclusive to other computers.

''Mario Kart 64
Only one egg made an appearance in Mario Kart 64. It was located in Yoshi Valley, near the last stretch before the grassy area and the finish line. The Egg moves about in a circular pattern. When a player runs into it, the Egg will smash the player, similar to when a player gets smashed when he/she is tiny. Maneuvering around this particular egg is difficult due to its tremendous size.

''Mario Kart: Double Dash!!
In Mario Kart: Double Dash!!, the Yoshi Egg is a special item, exclusive to Yoshi. When thrown, the Egg will home on the next place racer. If a player uses it while first, the egg will just follow down the track and break. Unlike the Red Shell, there is a certain amount of distance an egg needs before it cracks, and the red shell is continuous until it either goes off the course, goes into a wall, or hits the player. When it breaks, three random items will get thrown out, which can be Green Shells, Mushrooms, Bananas, Fake Item Boxs, Stars or Bob-ombs.

Mario Kart DS
In Mario Kart DS, the only appearance of an egg is in one of Yoshi's vehicles, called the Egg 1. It is a very simple kart, consisting of an egg, wheels, and tail pipes sticking up. It has very high acceleration and handling, but low weight and speed, much like the other lightweight vehicles. This is also one of the two vehicles that is most commonly used online, by snakers (the other is the Dry Bomber). Yoshi's symbol also takes a shape of an egg.

In a course called Yoshi Falls, the setting is in a road circling around a lake. In the middle of the lake contains a large Yoshi egg. However, it is just for looks and doesn't serve any purpose whatsoever, unlike the egg in Mario Kart 64.

Mario Kart Wii
The Yoshi Egg appears only as an emblem in the karts when Yoshi's chosen. There is also an egg that appears in Yoshi Falls, but the course was taken from the previous game, Mario Kart DS. Due to the lack of special items, the Yoshi and Birdo Egg fails to return as an item in Mario Kart Wii.

Mario Pinball Series
In the Game Boy Advance video game Mario Pinball Land, a Yoshi Egg act as a pinball that Mario could buy at the shop.

Comics
In the Club Nintendo comic "Ostern im Schwammerlland", the Easter bunny dropped a Yoshi Egg, out of which Yoshi emerged.

A Yoshi Egg played an important role in the comic "Mario in Mariozilla", published in the same magazine. In this story, some fog coming out of Kamek's broom shrinks the Magikoopa and Mario to ant-size. When they sit on a blade of grass waiting for help, Yoshi swallows them. All attempts to get the two out of Yoshi's mouth fail, but ultimately Dr. Light gets the idea that Yoshi laying an egg could be the solution to the problem. Yoshi obviously has difficulties doing so, but two hours later, he finally lays an egg. Light breaks it up and indeed Mario and Kamek come out of it.

Trivia

 * In the Yoshi's Story tech demo strangely the "Health" eggs had light green smiley faces on them.
 * In Mario & Luigi: Bowser's Inside Story, the Fawful Guys have an attack where a fawfulized Yoshi throws them in a yellow Yoshi egg.
 * In Super Mario 64, an unused Yoshi Egg texture can be found in the games coding.
 * A Yoshi egg can be received in Animal Crossing: City Folk for 1,000 shop points.
 * In Pokémon Ruby and Sapphire and the other Pokémon titles that were later released, the Pokémon eggs bear a resemblance to a Yoshi Egg.
 * One of the treasures found in Wario Land 2 looked just like a Yoshi Egg.
 * Although Yoshi Eggs don't appear in Super Mario Galaxy, there is a planet that looks just like a Yoshi Egg in the Good Egg Galaxy.