From the Super Mario Wiki
The Bathroom is a room in Area Two in Luigi's Mansion. It consists of a sink with a mirror, a bathtub, and a shelf where the key appears. When Luigi enters the room, he is attacked by two Grabbing Ghosts, a new type of ghost. After both of them are captured, Luigi receives the Key to the Ball Room and a message from Professor E. Gadd, giving him a tip on how to fight off the ghosts.
Ghosts in the Bathroom (1F)
Ghosts in the Bathroom (1F) in the PAL Hidden Mansion
Ghosts in the Bathroom (1F) during the blackout
Names in other languages