Glitch

Glitches are the term for when something strange happens in a Mario game. Two examples of glitches are Dark World and Minus World.

When glitches happen, either something weird will happen (such as Mario being able to walk underwater a glitch in Super Mario Sunshine) or the screen will freeze and sometimes some random pixels appear on screen. Some glitches are caused by damaged games. Some only actvate when the player presses a certain sequence of input commands (pressing buttons). Also, as seen in Super Mario 64, if you tilt the game console itself, Mario's limbs will be dislocated and become really weird, although you can still play in that position.