Mr. Bones

Mr. Bones, also referred to generically as "Skeletons," are white skeletal ghosts appearing only in the game Luigi's Mansion that are similar to Dry Bones. They attack by throwing bones at Luigi. These ghosts have thirty HP. Mr. Bones can also, like all other normal ghosts, be defeated by one of the three Elements. They are the only regular ghosts in the game with legs.

One is first encountered in the Boneyard where it was disturbed by Spooky's barking. It must be defeated in order to capture Spooky. Mr. Bones are also found in the Graveyard and have to be defeated to lure out Bogmire. More Mr. Bones are encountered in the Telephone Room after the blackout. As with many other ghosts, in the PAL version of the game, they are significantly more common in the game's Hidden Mansion.

Luigi's Mansion (Nintendo 3DS)

 * In-game description: "A skeletal ghost who throws his own bones and falls apart."

Reference
G. Bein Sig. Tuttossi