A Skull key is an item in Kirby Mass Attack. They are very easy to find, but when it is touched, the Kirbies will teleport to a dark area full of Skullies. One of the Skullies will be red and have a Treasure Chest. You need to defeat that one to get a medal. You could defeat the red Skully to leave the area, or you can wait for daytime.
- If you already have the medal from the area, the treasure chest will have fruit.