EDIT 1: Added more quotes and a list of all three alternate costumes.
Name: SpongeBob SquarePants
Residence: Bikini Bottom, Pacific Ocean
SpongeBob is the oldest of the original four Nicktoons team members, but oddly enough, he acts like the youngest. Despite this, he's pulled his light weight around on numerous occasions, like when he disabled a doomsday machine by simply pulling the plug or brought a giant orange blob monster to the side of good. Back in his homeworld, he's the best fry cook in town, a master jellyfisher, a bubble blowing artist, and even knows karate. His sponginess also allows him to be a skillful shape-shifter. With all this in mind, it's no wonder he's the most popular of the Nicktoons.
SpongeBob is pretty well balanced, but he's a real light weight, able to get knocked around easily.
B = Water Soak: SpongeBob doesn't soak up water so much as he soaks his opponents in it. Press B once to build up water, then press it again to squirt it out. The longer the charge, the further and stronger the squirt. It doesn't do a lot of damage, but it knocks opponents back quite a bit.
B + Side = Spatula Flip: Using his trusty spatula ("Spat"), SpongeBob can deflect any projectile attacks right back at whoever fired them. He can also flip opponents into facing the opposite direction, also causing a bit of damage.
B + Up = Inflatable Pants: SpongeBob brings back his old method of flight to give himself a brief (no pun intended) jettison into the air. It damages anyone caught in its flight path. At the end of the move, the pants pop and cause even more damage to anyone unfortunate enough to be in its radius.
B + Down = Bubble Blow: SpongeBob takes out his bubble wand to blow a bubble in a random shape, which he can then toss as a weapon. The damage it causes varies on the shape. If you're lucky enough to blow a bomb shape, be sure to use it wisely because it doesn't just pop... It explodes!
Standard = Hydrodynamic Spatula: SpongeBob spatula gets an upgrade, including port and starboard attachments and a turbo drive. All of his attacks involve the spatula during this and it packs a serious punch.
Super = Super Absorbancy: SpongeBob soaks up water and swells to ridiculous size. He then shoots out powerful streams in all directions. Bath delivery!
Ultimate = Goofy Goober ROCK!: SpongeBob turns into a rock-and-roll wizard with a magic peanut-shaped guitar! His righteous chops send out electric streams of energy that seek out all the opponents a KO them on impact!
Up D = SpongeBob plays his nose like a flute.
Side D = SpongeBob laughs uncontrollably, even to the point of bouncing a little.
Down D = SpongeBob briefly morphs into a "#1."
"I'm ready!" (being picked in the character selection)
"For the Krusty Krab!" (start of the match)
"Oh, I can walk the walk... But can I talk the talk?" (start of the match)
“I’m so sorry, Patrick! It’s like my actions are coming from someone else!” (KOing Patrick)
"Who's the King of Karate now?" (KOing Sandy)
"Nothing personal, but air is my natural enemy." (KOing Aang)
“Ooh… Beating up a blind girl cannot be good for my image…” (KOing Toph)
“Next time, your highness, try not to fight water with fire.” (KOing Zuko)
"I know I just beat you up, but can you wish me up a driver's license?" (KOing Timmy)
"Team founder or not, you're going down!" (KOing Jimmy)
"Oops! Sorry Danny! You just scared me, is all!" (KOing Danny)
“El Tigre, meet El Esponja!” (KOing El Tigre)
“Looks like someone needs to be waterproofed...” (KOing Jenny)
“Ever thought about something more productive than global destruction?” (KOing ZIM)
"Who's hungry?" (activating SplatDown)
"Bath delivery!" (activating Super SplatDown)
"ARE YOU READY TO ROCK?!" (activating Ultimate SplatDown)
"Victory Screech! WHOLOLOLOLOLOLOLOOO!!!" (victory screen)
"Who put you on the planet?" (victory screen)
(more quotes will be added as more characters are revealed)