When a spelunker dies, and until they are revived, in either Co-op or deathmatch (given the Ghost option is active), they will become a spelunker ghost. Spelunker ghosts can move in any direction(with a slippery traction), through walls, and can blow puffs of air with X/Square, which push items and enemies in a 2 block range, stunning them, with the same effect that using a whip has, except dealing 0 damage. They also have the ability to spin in a circle with the rope button, stretch themselves vertically with the bomb button, and pulsate a few times with the jump button. (When I play co-op, I like to let the other person die, because I'm heartless, and then call him/her "trigger". they can trigger dart traps, blow shopkeepers into the abyss in the ice caves, open boxes out of reach, and blow items down.)
If a camera is used on a spelunker ghost, they will freeze and perform a pose of some sort, unique to each spelunker. They are also able to make a pose while performing a spin.