The area that the Kirbys arrive in after they grab the Skull Key
A Skull Key is an item found in Kirby Mass Attack. It is a key that can be found in a random area throughout a stage. If one is obtained, the player's Kirbys will be sucked in by a portal that leads to a dark area. The Skull Gang, a large group of Skullys, will then appear, ambushing your team. They can be defeated with just a few Kirbys, but can snatch Kirbys if they are not watched.
The way to escape from the Skull Gang is by defeating them and the red Skully that is holds a special gold chest with purple marks. If it is destroyed, the chest will fall to the ground and the other Skullys will fly away and disappear.
Using the Skull Key, the chest can be opened. Once opened, you will recieve a medal. If it has been previously obtained, fruit will come out of the chest instead. After the reward is recieved, the portal will come back, taking the Kirbys back to where they picked up the key.