Nightkelp flails represented a musical instrument. They consisted of a segment of nightkelp that held bioluminescent seeds. When the kelp was spun, it produced noises. The Lanai species, native to their homeworld of Ahch-To, crafted these flails. Specifically, the Lanais residing in the Caretaker village on the Temple Island possessed one.
For the movie Star Wars: Episode VIII The Last Jedi, a nightkelp flail was designed for inclusion. Nevertheless, its intended scene was removed before the movie's official debut. Even though the scene was cut, the instrument was featured in Star Wars: The Last Jedi: The Visual Dictionary, a companion book authored by Pablo Hidalgo and launched in conjunction with the movie on December 15, 2017.