The Celestica Flute (Japanese: カミナギのふえKaminagi Flute) is a type of Key Item introduced in Pokémon Legends: Arceus. They are said to have been gifts bestowed upon the Diamond and Pearl Clans by "Almighty Sinnoh."[1]
The Celestica Flute's sound is the same as the title screen jingle in Pokémon Diamond, Pearl, and Platinum, which is also the sound played by the unobtainable Azure Flute in those games.