The Flash Liquidizing Ultra Dousing Device, or FLUDD, is Mario's main tool and companion during his visit to Isle Delfino in the GameCube platformer Super Mario Sunshine. FLUDD offers Mario advice and helps him throughout his adventure. However, Super Mario Sunshine features multiple secret platforming areas where FLUDD is taken away by the mysterious and evil Shadow Mario, and Mario must complete the area without the aid of his companion.
FLUDD also makes an appearance in Super Smash Bros. Brawl, the third entry in Nintendo's popular fighting series. Mario uses FLUDD in one of his special attacks in which he sprays a powerful stream of water forward through FLUDD's Spray Nozzle. Mario can alter the angle of the water's trajectory upwards or downwards, and while this attack does not inflict any damage onto opponents, the blast of water propels enemies backwards, making it ideal for keeping them at a distance or pushing them clear off of the stage and to their deaths. Mario can also charge this attack to increase the pressure of the water spray.
FLUDD features four different nozzles in Super Mario Sunshine, each of which gives Mario a new ability.
The Spray Nozzle The Spray Nozzle allows Mario to squirt enemies and objects with water, which is ideal for cleaning up Isle Delfino and also can be used to stun or defeat enemies. This nozzle even allows Mario to steer boats, although it is quite difficult to do. By shooting FLUDD's water spray in the opposite direction of where Mario wants to go, he is able to steer since the force of the water propels the boat in the opposite direction. With this nozzle, FLUDD has its default appearance and shoots the water forward in a stream. This is FLUDD's standard nozzle and you will always have it as your disposal, as long as you're carrying FLUDD.
The Hover Nozzle This nozzle transforms FLUDD into a jetpack-like device. It equally shoots waterdownwards on both sides of Mario, and the force of the water pushes Mario's body slightly upward. Using this nozzle at the height of Mario's jump lets him reach marginally higher altitudes. The Hover Nozzle, however, is most frequently used to allow Mario to hover in the air for short periods of time. This is most convenient for all of the platforming in Super Mario Sunshine. It is a helpful tool that allows you to recover from missed jumps, and travel longer distances while in the air. Also, since it sprays water downwards, it's useful for stunning enemies below Mario, many of which he can then drop on top of to defeat.
The Rocket Nozzle The Rocket Nozzle is one of the more rare nozzles you'll find in Super Mario Sunshine. With this nozzle, FLUDD charges up a strong blast of water that shoots Mario high up into the sky like a rocket. Although it is not common in the game, it is used to reach high altititudes, which otherwise are almost always out of Mario's reach. It has to charge for a few seconds before it launches Mario upwards, and because it consumes a fairly large amount of water at a time, you'll only be able to get a few uses out of it before needing to refill it with more water. Though it is not used often throughout the game, it has a prominent role against the game's final boss.
This is the rarest nozzle you can find in Super Mario Sunshine. With FLUDD strapped onto his back while equipped with this nozzle, Mario can travel at high speeds on land and in water.
FLUDD transforms into a fan-like propeller that gives Mario a burst of speed when running and jumping on foot. However, this nozzle drains FLUDD's water tank pretty quickly when he's on land. Once he steps foot into water, Mario flies through the water at turbo speed. This nozzle also refills as you speed through the water, allowing you to continue using it for long durations of times, so long as you keep your feet wet. It's primary function in the game is to allow Mario to break through certain doors, which can't be opened by any other means.