FLUDD is a water-spraying device featured in the video game series Super Mario. It is primarily used by Mario in the game Super Mario Sunshine to clean up pollution and defeat enemies. The device can spray water in various ways, allowing players to solve puzzles and navigate the environment. In addition to cleaning, FLUDD has different nozzles that provide unique abilities. For example, the Squirt Nozzle allows for continuous water spraying, while the Rocket Nozzle enables Mario to reach high places. Overall, FLUDD plays a crucial role in gameplay mechanics and exploration.