F.L.U.D.D. (ポンプ, Pump), short for Flash Liquidizer Ultra Dousing Device, is Mario's down special move since Super Smash Bros. Brawl. The move involves Mario taking out F.L.U.D.D. and charging it up for about a second and a half.
F.L.U.D.D. is an auto-charge special; so thus, pressing the special move button again while charging, or using the move after being fully charged, results in F.L.U.D.D. firing twelve globs of water a distance dependent on the charge, Like other such auto-charge moves, pressing a shield button while charging will cancel and save the charge as well as tilting left or right will make him roll with the same cancel effect (shielding/grabbing while charging in the air would instead cancel it with an air dodge), while getting hit during charging period will lose said charge.
The attack does not deal any damage, instead simply pushing opponents based on the charge level. The water spray can be aimed vertically with the control stick. Should Mario use the move, he will be pushed backwards. This can aid horizontal recovery in midair.
In most situations, being pushed by F.L.U.D.D. is merely a nuisance, not doing much but forcing combatants apart. When used judiciously, however, F.L.U.D.D. can be highly effective. Opponents that are attacking will clang with each segment of the water stream, trapping them in significant freeze frames and possibly allowing Mario to approach. More notable is the move's power at gimping - as it deals no damage and doesn't cause the opponent to flinch, it can push opponents away from the stage during their recovery without giving them another chance to use it, often not only further distancing them from the stage but providing momentum in the wrong direction.
It was noted on the Dojo that this move can be charged while shielding; however this is not true, as shielding merely saves the current charge.
With increased pushforce and range added to F.L.U.D.D. in Smash 4, Mario has a much easier time setting up his opponents to be Caped while they are still off stage. The term "FLUping" was coined by Brawl Karter to describe using the moves in tandem (F.L.U.D.D. to Cape) and denying the opponent the ability to safely recover back to the ledge/stage.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
F.L.U.D.D. originally appeared in Super Mario Sunshine for the Nintendo GameCube. Mario encounters the device at the beginning of his vacation to Isle Delfino. It introduces itself and Mario equips it, and it comes in handy when he is forced to clean up the pollution on Isle Delfino. Although its main use is to wash away poisonous goo, F.L.U.D.D. doubles as a weapon and can be used to push small enemies away or stun them. If the water tank is emptied, Mario is required to refill it in the nearest source of water. In Brawl, F.L.U.D.D. uses the secondary purpose from Super Mario Sunshine as a defensive measure against opponents.
An aqua jump occurs when Mario's F.L.U.D.D. or Squirtle's Water Gun hits any jumping character just before they begin to lose momentum. This causes the jump to rapidly speed up and double in height. It is technically not so much of a technique as a misuse of the two aforementioned moves.
Super Smash Bros. Brawl
Super Smash Bros. for Wii U