Chase the Shadow Mario. Go into the hotel. The ghosts disguise themselves as Shadow Mario!! Very cute. the ghost ones have white flashes and are stationary.

Triangle on second floor wall matches blue coin down by bar on first floor. For first floor one wall jump up middle pole to get up to 2nd floor. Blast him until he falls down and then grab him.

blue coin first room on left

3rd floor above staircase red M blue coin

Super Mario Sunshine Walkthrough