The Cave is a stage in King of Stories. It is not from any particular universe in the games. Samus, Donkey Kong, Diddy Kong, Excitebiker, Little Mac and Captain Falcon are playable here.
The Cave, as its name states, is an underground cave, very similar to the one in Brawl with the same name. It features many, dark paths and hidden doors. At some points of the stage, rocks will start falling and the floor will fall off. It features many enemies to battle and many hazards. Samus and the characters mentioned above head there in persuit for Ridley, who has stolen a gemstone.