Choose Battle Mode and any kind of match. Enter a User ID at the User Setup menu. Now at the Character Select screen, hold L1 + L2 + R1 + R2 and quickly enter the following:
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Arii
X, Square, Triangle, Circle, Square.

Briggs (alternate costume)
X, Triangle., Circle, Square, Circle.

Briggs (alternate costume)
X, Triangle, Square, X, Circle.

Carla
X, Square, X, X, X.

Chukklez
Square, Square, Triangle, X, Circle.

Cruz
Circle, Triangle, X, X, Circle.

D-Mob
Square, Triangle, Circle, X, Circle.

D-Mob (alternate costume)
Square, Square, Triangle, Square, Square.

Dan G
X, Circle, X, Circle, Square.

Deebo
Circle, Circle, X, X, Triangle.

Deja
Circle, Square, Circle(2), X.

DMX
Circle, X, Circle, Triangle, Square.

Drake
Triangle, Square, Circle, X, X.

Drake (alternate costume)
X, Triangle, Triangle, Circle, Circle.

Funkmaster Flex
Circle, Triangle, Circle, Circle, Square.

Headache
Triangle, Triangle, Triangle, Square, Circle.

House
Triangle, X, Triangle, Circle, X.

Iceberg
Square, Triangle, Circle, Square, Circle.

Ludacris
Circle, Circle, Circle, Square, Triangle.

Manny (alternate costume)
Circle, Square, Circle, Square, Circle.

Masa
X, Circle, Triangle, Square, Square.

Method Man
Square, Circle, X, Triangle, Circle.

Moses
Triangle, Triangle, Square, Square, X.

N.O.R.E.
Circle, Square, Triangle, X, Circle.

Nyne
Square, Circle, X, X, Triangle.

Omar
Circle, Circle, Square, Triangle, Triangle.

Opal
Circle, Circle, Square, Square, Triangle.

Peewee
X, X, Square, Triangle, Square.

Peewee (alternate costume)
X, Triangle, Triangle, Square, Circle.

Penny
X, X, X, Triangle, Circle.

Pockets
Triangle, Square, Circle, Square, X.

Proof (alternate costume)
X, Square, Triangle, Square, Circle.

Razor
Triangle, Square, Triangle, Circle, X.

Razor (alternate costume)
Square, Circle, X, Triangle, Triangle.

Redman
Circle, Circle, Triangle, Square, X.

Ruffneck
X, Square, X, Triangle, Circle.

Ruffneck (alternate costume)
Square, Circle, Triangle, X, Square.

Scarface
Circle, Square, X, Triangle, Square.

Sketch
Triangle, Triangle, Circle, Square, X.

Snowman
Triangle, Triangle, X, X, Circle.

Spider (alternate costume)
Square, Triangle, X, Square, Circle.

Steel
X, Triangle, Circle, Circle, Triangle.

T'ai
Circle, Circle, Square, X, Circle.

Zaheer
Triangle, Triangle, Square, X, X.
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