Skeleton Ghosts follow a specific movement pattern when attacking. When they first appear, they will first just be a pile of bones. After appearing, they reassemble themselves with a clattering noise, then they throw a bone at Luigi, disassemble themselves after which they will move away somewhere else before throwing another bone at Luigi, repeating the sequence.
One named Mr. Bones appears in the yard where Spooky sleeps. After Luigi wakes Spooky up, he will eventually get angry with his loud barking, and say, "For the luvva dirt, make that yappy dog be quiet!" Despite this, he does nothing to attempt to make Spooky be quiet, instead makes the fight harder for Luigi by throwing bones at him. Eventually, Luigi can suck him up and a bone will come flying out and attract Spooky's attention, making him vulnerable to suck up. Despite Mr. Bones having an actual name, he is not a gallery ghost. Three of them also appear in the Graveyard (5 in the Hidden Mansion) which Luigi has to defeat in order to battle Bogmire. They also appear in the Telephone Room in all chests except for one.
- Mr. Bones is the only Skeleton Ghost to have a line of dialogue. In fact, he's also the only non-Portrait Ghost who can speak.