Pedestal Key

From the Super Mario Wiki

Pedestal Keys are Palace Keys found in the Riddle Tower of the Palace of Shadow in Paper Mario: The Thousand-Year Door. The Star Key is required for Mario to unlock the pedestals. Unfortunately, Gloomtail is guarding it (or rather, swallowing it), so Mario and his pals had to defeat Gloomtail to get the Star Key. By placing the 8 Pedestal Keys in the pedestals, Mario will unlock the secret path to the Shadow Queen's throne room (and crypt, which is hidden behind her throne).

Keys
Black Key | Blue Key | Card Key | Castle Bleck Key | Elevator Key | Fortress Key | House Key | Key | Luigi Key | Mario Key | Odd Key | Palace Key | Pedestal Key | Random House Key | Red Key | Ruins Key | Shop Key | Skeleton Key | Station Key | Steeple Key | Storage Key | Storeroom Key | Warehouse Key | Wario Key | Yakkey