The Floating Whirlindas, the Dancing Couple are two of the Portrait Ghosts who escaped imprisonment in Luigi's Mansion.
The Floating Whirlindas used to be the local waltz champions, but unfortunately they aren't allowed to compete anymore because their feet can't touch the ground. The Whirlindas were found in the Ballroom on the first floor's east wing of the mansion. They appeared after you defeat the six Shy Guys in the room, making the dancing floor spin as they waltzed. The green plumber had to wait until they bowed, making them vulnerable. After some medium tugs, Luigi earned the key to the Storage Room.
Note: Unlike Henry and Orville and The Clockwork Soldiers, the Whirlindas are both caught at once.