This glitch, found in Ultimate Marvel vs. Capcom 3, has
apparently been known or observed before; now there's a tutorial
for how to enter the game's "Reverse World," in which all
combatants are silhouetted and all inputs are reversed.  It's
preceded by a switching (and locking) of the camera to its
Z-axis, meaning left and right on your stick moves your fighter
forward (closer to the screen) or backward (into the distance).
Commenters on Shoryuken, where the tutorial was first posted,
believe that reverse-world entry is limited only to the game's
Xbox 360 version. Some PS3 users say they can only get a black
screen.  See the above video for detailed instruction, but more
or less, after the Z-axis glitch happens, Deadpool's level 3
super will send you to Reverse World. And it's trippy.  UMvC3
Z-Axis/Reverse World Glitch Tutorial [Shoryuken]