Captain Fishook is the thirteenth boss encountered in Luigi's Mansion 3, who haunts The Spectral Catch and guards both the thirteenth floor's elevator button and Yellow Toad's portrait. He is one of three non-humanoid bosses in the game, the others being Polterkitty and King Boo.


Captain Fishook is a ghostly great white shark wearing an eyepatch which conceals the thirteenth floor's elevator button, his "good eye" being red and pupilless. He has a golden ring on his dorsal fin, his right fin is replaced with a hook-like scythe, and he appears to have a golden tooth.

Captain Fishook appears shortly after embarking on his ship, swimming up on the side behind Luigi. After leaping aboard, he reveals the thirteenth floor elevator button underneath his eyepatch before possessing part of the ship's deck, warping it into a semblance of his own visage.