CP1

CP1 (or Checkpoint 1) is a term used by the Super Mario Maker and the Super Mario romhacking internet communities referring to a designed troll element that usually transports the player to either the first or the previous checkpoint of the level, making them lose a significant portion of their progress.

The checkpoint is not necessarily the first one that the player crosses, as the game allows for two checkpoints to be placed. The checkpoint crossed can just as easily force the player to the very beginning of the level as well. The CP1 can be accessed through a door or a pipe, or simply, by dropping the player on top of it.

The player is usually presented with two or more choices in order to proceed, but if all those choices lead to the CP1, it can be used to make the player consider that the mistake that was made occurred at an earlier point.

Alternatively, the player may be taken to the beginning of the level itself and not to the first checkpoint. This circumstance is denominated CP0 (Checkpoint 0).