The music in Fountain Of Dreams is an orchestral remix of the Gourmet Race theme from Kirby Super Star. This remix was used in Kirby: Nightmare in Dream Land during the battle against King Dedede, and has since been recognized as the fountain's theme. Kirby: Nightmare in Dream Land was most likely in development during the creation of Super Smash Bros. Melee, and so the fountain's music was added as a teaser for the upcoming GBA game.
Contributed by likiji1234