Mach Rider
A - Lifts his bike's front wheel off the ground and spins it, dealing several low-damage hits.
AA - Repeatedly spins the front wheel.
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Side+A - Whips the front of his bike across in front of him.
Down+A - Lifts his front wheel up, then slams it down, damaging in front of him.
Up+A - Does a handstand on his bike seat, and thrusts both feet upwards.
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Side Smash+A - A short, forward thrusting wheelie.
Down Smash+A - Lifts up the front of his bike. Before that part hits ground, his back goes up. His front and back ends land consectively, creating strong shockwaves on both sides.
Up Smash+A - Uber-wheelie! A full backflip, bike and all.
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Nair - Does a lateral spin with his bike.
Fair - Front wheel spin.
Bair - Kicks out with one foot behind him.
Uair - Gripping the handlebars, he whips the bike out above him, then pulls it back under himself.
Dair - Swings the front of his bike across in front of him, spiking the opponent (think Samus' Dair, only with a motorcycle).
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Grab - Turns his bike sideways, then reaches out with one hand. A running grab would produce a sliding effect, with Yoshi-esque lag.
F Throw - Grips the enemy's collar, then winds up with this other arm and delivers a straight to the jaw that sends the opponent sailing forwards.
B Throw - Tosses the enemy over and behind him, then, gripping the handlebars, double kicks behind him, hitting the enemy.
U Throw - Tosses the enemy with both hands lightly upwards, then backflips his bike. The front wheel does a few points of damage, then the back wheel sends them flying upwards.
D Throw - Drops the enemy to the ground, then places the front wheel on top of them and revs the engine.
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B: Backfire - His engine pops, sending him forward in a short burst. At the end, he turns around. If you press B again right after he switches directions, the move goes off again, leading to an endless chain of backfires.
Side+B: Ripcord - Revs his engine, then releases his bike. It crashes forwards, then u-turns back into his waiting hands. The danger here is that he doesn't move while his bike isn't in his hands.
Up+B: Up In Smoke - In a burst of smoke, he separates into five or six shards, then reforms above his original position. Enemies caught by the shards take damage. (Obviously ripped from Deathborne's set)
Down+B: Spin Out - His engine bursts into flame, and his bike does a series of close, repeated circles, ending in a small explosion of fire (Mario Tornado-esque move).
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Brawl Attack: Gunblaze - For a short time, Mach Rider's machineguns fire an endless stream of bullets (or lasers...whatever), no matter what he's doing. The rounds have a limited range, and do less damage than Sheik's needles, but they're endless, and when used in conjunction with Spin Out or his Dair, can create some very heavy damage totals.
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So there you go, an awesome moveset for an awesome character, that would bring a whole other dimension to the Smash Bros. universe. Tell me again why this is a bad idea?
EDIT - Oh, hold on. Looks like I missed some stuff.
Edge grab: he'd hold the edge with one hand, while his other hand gripped the back wheel of his bike. His recovery attack writes itself on that! (Hint: Whips the bike in an overhead arch, then jumps onto it. The bike deals the damage.)
Double jump: His first jump is created by him quickly slamming his front tire into the ground, creating a flipping jump. His second comes from a burst of energy out of his exhaust. It should be noted that he'd have Bowser-quality jump height.
Crawl: Eh, he couldn't do this one. But hey, they only gave us walljumping with like, three characters in Melee. I don't think crawling's going to be an incredibly necessary technique.