This is a cute little glitch that allows the possibilities for further glitches such as the Monkey Walk. Like the name states, the gun you pick while perfoming this glitch will be invisible, you cannot see it, it will look as you are holding nothing.
Anyways, heres how it is performed...
1) Get to any Gun and step on it.
2) Press left or right on Dpad, LT+RT+X and you'll have the invisible gun.
3) Change to the other gun and come back to the switched gun, you'll have the Monkey Walk (also known as Monkey Stance).
4) Change to any other gun and come back to the switched gun again, and voila (See video for what Viola means).
