Egg

Throughout the Marioverse, Eggs have many uses. In the Paper Mario series they restore 5 HP and make a Fried Egg when cooked.

Yoshi Eggs
Main Article: Yoshi Egg

The spotted Yoshi Eggs are white with specifically-colored spots.

Yoshi Eggs are able to be used as projectile weapons--mainly by the Yoshis themselves.

Birdo Eggs
Main Article: Birdo Egg

Although recent discoveries have proven that Birdos can spit pink Yoshi Eggs, most Birdo Eggs are non-spotted. A Birdo will spit Birdo Eggs out of its cannon-like snout, and use the eggs like bullets. The player can jump on these to get a free ride.

Mystic Egg
Main Article: Mystic Egg

Found only in the Boggly Woods, Mystic Eggs are from an unknown creature. Nobody knows where to find them except the Puni girl, Petuni. For a certain favor, Mario can obtain Mystic Eggs from Petuni during the events of Paper Mario: The Thousand Year Door. Like in its prequel, the egg recovers 5 HP and may be used in all sorts of recipes.

Mystic Egg Recipes

 * Egg = Fried Egg
 * Fire Flower + Egg = Egg Bomb
 * Horsetail + Egg = Omelette Meal
 * Mushroom + Egg = Omelette Meal
 * Super Mushroom + Egg = Omelette Meal
 * Ultra Mushroom + Egg = Omelette Meal
 * Life Shroom + Egg = Omelette Meal
 * Dried Bouquet + Egg = Space Food
 * Cake Mix + Egg = Zess Cookie
 * Fresh Pasta + Egg = Zess Dinner

Mario Kart: Double Dash!!
It is a special attack in Mario Kart: Double Dash!!. It is exclusive to Yoshi and Birdo. It won't stop rolling until it rolls an entire lap or collides into a driver. Collision causes the player to crash, and spills three random items onto the track. This can include Green Shells, Mushrooms, Bananas, and maybe a Star or Bob-omb. Unlike a Red Shell, it breaks after a certain amount of time if it doesn't get to its target.

Super Smash Bros. Series
In both Super Smash Bros. games, eggs have made an appearance as an item. Only dropped by the Pokémon Chansey, it had an item inside, and could be thrown at an opponent for damage.