('Hotel', as heard in Hotel)
'Hotel', alongside 'It's Showtime!', 'Metal Crusher', and 'Oh!', serve as Mettaton's leitmotifs, appearing in various contexts relating to the character.
(Mind you, it's highly recommended to read these articles together!)
'Hotel' serves as an extraneous melody pertaining to Mettaton's cooking show, Cooking With a Killer Robot, and his hotel, the MTT Resort.