FLUDD
FLUDD (Flash Liquidizer Ultra Dousing Device) is a water pack from Super Mario Sunshine. It can be used by Mario to spray water, by pressing the R button. With this, Mario can perform many tasks from enhancing his acrobatics to cleaning off graffiti.
FLUDD and its nozzles were invented by E. Gadd. FLUDD seems to possess artificial intelligence, and can feel emotions such as joy and fear. Because of this, the water pack acts as Mario's sidekick and guide during his stay on Isle Delfino, giving Mario (and sometimes the player) handy advice.
After Mario's battle with Bowser, FLUDD brakes down, asking Mario if it was of assistance before it shuts off. However, this doesn't spell the end for the sentient water pack; Peach's Toads fix it up and return it to Mario. Right as the game ends, FLUDD happily exclaims, "The vacation starts now."
Trivia
When FLUDD scans Mario, a little window in the bottom left corner shows various Mario games. After Bowser is beaten at the end and FLUDD is looking at Mario, the window shows "Game Over".
Nozzles
Squirt nozzle - The basic nozzle, which allows Mario to shoot water at enemies, and he is always equipped with this nozzle. The Squirt and Hover nozzles are the first two nozzles Mario starts with.
Hover nozzle - This nozzle allows Mario to hover in the air for a short time.
Rocket nozzle - This nozzle allows Mario to shoot up high into the air.
Turbo nozzle - This nozzle allows Mario to run at an extremely fast speed on land, or swim at an extremely fast speed in water.
