From the Super Mario Wiki
When Luigi enters the Tea Room, haunted dishes from the shelves fly at him. Two White Grabbing Ghosts appear and can hold Luigi in place, making Luigi vulnerable. After Luigi sucks in the two ghosts, a large white treasure chest with the Ice Element Medal inside appears on the left table. To reach the chest, Luigi can use the two Gravity Arrows in the room to get on the table and open the chest.
The Tea Room is a symmetrical room, containing two tables with four chairs each. A small box sits on the eastern table. There are also two cabinets that take up the entire length and height of the east and west walls. A crystal chandelier hangs in the middle of it.
There is a 20% chance a Gold Ghost Mouse appears as soon as Luigi enters the room. A cheese housing an additional Gold Ghost Mouse can be found behind the left table.
Ghosts in the Tea Room in the PAL Hidden Mansion