Might And Magic Heroes 6
Mysterious Egg
Once you get the Mysterious Egg item, do not sell it. At first it does not do anything. However, if you put it in one of your pocket slots, it will hatch into the Golden Rooster after approximately 2-3 in-game weeks. The Golden Rooster gives 2,000 gold every day.
The image featured at the top of this post is ©The Legend of Heroes: Trails of Cold Steel III key art / Original