The Cave Planet Cavius (originally Cavios) is the cavern star from the sub-game Milky Way Wishes of Kirby Super Star and its remake Kirby Super Star Ultra and exists in a galaxy near Planet Popstar. It is the fifth planet, following Hotbeat and preceding Mekkai; however, because Milky Way Wishes is a non-linear game, it can be played at any time. The surface of Cavius is mountainous, but it also has many craters. Its first main area is a mountain, which leads to a system of caves that contain rooms with all the mid-bosses faced until that point in the game. Near the core of Cavius is a large water reservoir.
Due to the way copying abilities works in Milky Way Wishes, abilities can only be obtained from enemies using the Copy ability provided by the Copy Copy Essence Deluxe (though there are a few exceptions).
- Bomb: Defeating Poppy Bros. Sr. grants the Bomb Copy Essence Deluxe.
- Hammer: Defeating Bonkers grants the Hammer Copy Essence Deluxe.
- Stone: After the room filled with Mid-bosses, destroy the Bomb Block to release the water. Go into the water pool and press the Switch to the right. Go back down and enter the door the was obstructed by a gate.