Mystery Egg, also known as the Egg, is an enemy from the game Final Fantasy IV. It contains a monster within, and if enough time expires during the battle, the egg will hatch, revealing a random monster inside. Destroying the Mystery Egg before this happens will prevent hatching, but no EXP or gil will be awarded. Known monsters that can hatch from the Mystery Egg are: Black Lizard, Lamia, Nagaraja and Green Dragon.