Sonic from Sonic the Hedgehog for the Super Mugen Bros project.
By Shazzo the Hedgehog.

Origin:
Well, after getting into Mugen recently, I instantly desired to make my own character. However,
since I didn't have Photoshop or Paint Shop Pro, & Fighter Factory was a foreign language to me,
I decided I'd start out by editing an existing character. That's when I found CvS Axel by
EasyChar. Then of course there was the palette issue. MakeAct and Pal2act were useless, so I
tried an alternative strategy, using Paint and Photo Express. And it worked! So after
a few hours of editing, I transformed Axel into his current form - Sonic.

Why:
Sonic is one of the characters for Super Mugen Bros.

Moves:
Standing
A/X - Punch
B/Y - Kick 1
C/Z - Kick 2

Crouching
SMB uses weapon modes rather than crouches. These moves are stronger but take longer to connect.
Sonic's weapon mode is the blue chaos emerald.

A/X - Charged punch
B/Y - Charged kick 1
C/Z - Charged kick 2

Midair
A/X - Kick 1
B/Y - Kick 2
C/Z - Spin

Specials
Down, down-forward, forward + X/Y/Z - Spin dash
Down, down-forward, forward + A/B/C - Chaos shockwave - Sonic uses the chaos emerald to summon
a shockwave that knocks the opponent away.
Down, down-back, back + X/Y/Z - Sonic spin

Supers
Level 1
Down, down-forward, forward, X+Y - Chaos Shock - Sonic's emerald powers up, and unleashes a beam
of concentrated chaos energy.

Level 2
Down, down-forward, forward, A+B - Sonic Lightning - Sonic charges himself up with the chaos 
emerald and lunges at the opponent in a burst of blue flame.

Sources/Thanks to:
Sprites: A Sprites Database I found on Google, the Spriters' Resource, and the MFZ.
Sound: Sonic Fan Games HQ.
Coding: EasyChar