Floor 13: Fitness Center

Elevator Hall: Step on the circular platform. Use Gooigi to weigh it down, revealing the Yellow Gem on eastern shelves. Collect the gem, Coins, and Gold Bars. Suck Coins from Hammer statues and the elevator. Examine the southeastern trashcan for Cash. Interact with the ringing telephone to hear a clue. Use Dark Light beside the door to reveal a G-Bag for Bills.

Gym Lobby: Collect Cash from magazines and a trashcan. Use a Suction Shot on the northern medallion for Bills. On the northern desk, pull the northern side to reveal a secret compartment with Coins and G-Bags. Collect white towels on the left shelves for Treasure, and Coins from red towels. Activate the water fountain's strobe switch (no significant effect). Reveal and ring the bell on the desk using Dark Light. Ring it thrice to reveal a Gem Goob and acquire the Clear Gem. The western door is locked; proceed through the door near the desk on the right.

Pool - Back Access: Burst near the fire hydrant in the southeastern corner for Coins. Collect Cash on the eastern wall frame. Head down the stairs. Use Dark Light under the northern arrow sign to find a chest with Coins and three Pearls. Find an invisible trashcan in the southwestern corner for Gold. The door to the pool is blocked by towels; return to the Gym Lobby.

Gym Lobby (Revisited): A volleyball will break the northern window, allowing a view into the pool. After a ghost smashes another volleyball, four Goobs and a Slinker will appear. Defeat them, paying attention to the two Goobs wearing sunglasses. The Key to the next room will be dropped. Use it on the western door.

Locker Room: An Oozer will appear and hide in a locker. Slam the locker to reveal the Oozer, Mini Goobs, and Mini Hammers. Defeat them, using the Oozer against the mini ghosts. Collect Bills from the easternmost shelf and potential Cash from other shelves. Collect Coins from the western shelf. Head down the steps to the left. Shoot a football or boxing glove at the pool sign on the northern wall to reveal the Blue Gem. Collect Gold Bars and a Pearl from the right shelf, Money from the left cabinet, and Bills near the plant. Blow on the rug from the southern side to reveal a hole for Gooigi. Send Gooigi through the wall of skulls and yellow pipe for Gold. Head east to find Rats and Gold Rats. Suck them up, leading them to Luigi. Suck up all mice to achieve "Get All Locker Room Mice". The northern door is blocked; proceed through the western door.

Weight Room: Two Hammers will appear and attack. This is a boss battle.