Ghost is one of Kirby's many copy abilities, and a rather special one at that. It originated in Kirby: Squeak Squad as an unlockable ability and has only appears in that game.
Ghost can only be copied from the unique mini-boss, Tedhaun. Tedhauns replace one mini-boss from each level after all Ghost Medal pieces have been unlocked.
Ghost gives Kirby the power to control enemies and use their powers as his own. Ironically, while ghosts are usually portrayed as having the ability to pass through solid objects, Ghost Kirby does not have that ability; he can't even travel down ladders or pass-through floors that the regular Kirby can pass through. It also cannot attack mini-bosses or bosses without possessing a regular enemy beforehand whose attacks aren't limited to ramming.
Kirby charges forward. When he comes in contact with an enemy, he possesses them. In this state, he can use their attacks and they all have unlimited multi-jumps. While charging, Ghost Kirby is invincible. Also note that if Kirby is controlling an enemy, Kirby doesn't get hurt at all; the controlled enemy can be used as a living shield.
None
Erase
X (when possessing enemy)
Once the enemy is under Kirby's influence, he may suck up the enemy into his ghostly cloak, instantly disposing of them. Also, if the possessed enemy grabs an enemy, that enemy will too be destroyed when Kirby performs the "Erase" move.
Acchi fires a small fireball forward. The fireball continues to burn upon making contact with the ground for several seconds.
Fire
Meteor
↑ + B
Acchi shoots a small fireball slightly higher then normal. Once again, the fireball continues to burn upon coming in contact with the ground for several seconds.
When underwater, Blipper has no problem moving around and is easy to control. When outside of water, however, Blipper will be more difficult to control, and bounces around awkwardly.
By pressing B, Gaw Gaw slices enemies with its claw, which it will swing in the desired direction with the use of the D-Pad. This attack can also dig through dirt.
None
Maul
A + B
Gaw Gaw lunges forward and bites an enemy's face, defeating them in one hit. By climbing a wall with ↑, Gaw Gaw does not need the A button to be pressed for this move.
Uja will start out as a strange, black cloud. Pressing "A" turns the cloud into a sword. In sword mode, it attacks with the "B" button. By pressing "B" as a cloud, it becomes a hand that can use grab attacks on enemies.
Ghost Kirby isn't playable, but he serves as the ghost for the player's previous race in Gourmet Race. (Similar to the Mario Kart series) If Kirby chooses to redo the same course that time around, a ghost is created that the player can race. As most ghosts, the Ghost Kirby travels on the same path that the player traveled in the past race. Ghost Kirby looks exactly the same as he did in Squeak Squad, except he is now always surrounded by a bright bluish-white glow. He also goes through Star Blocks without breaking them.
Trivia
In the Kirby: Right Back at Ya! Halloween special, Kirby puts a bedsheet over him, resembling Ghost Kirby, then inflates and flies around, accidentally scaring Tiff.
When a bubble item is sent to Ghost Kirby's mouth (eg: a Star Bubble,) he will inflate and drop on the ground and remain motionless until the item is discarded; this is also the same deal with the UFO ability.
When Kirby transforms to any ability, he does a waving-walking pose, when he does this with the Ghost ability, a blue shoe is revealed.
