From the Super Mario Wiki
Retrieved from "https://www.mariowiki.com/index.php?title=504_Bathroom&oldid=2817319"
There is a bathtub, sink, and toilet in the 504 Bathroom. There are two coins in the sink. There are also coins which can be seen through the sink mirror. If Luigi pulls the shower drape, a Spider will appear. Additionally, there is a drain in the middle of the floor which Gooigi can fall through to get to a secret area with two bags full of money.