Playing Super Mario 64 Crashes Paper Mario

Playing Super Mario Crashes Paper Mario is the name given to a phenomenon in which simply having booted up a copy of Super Mario 64 and then attempting to play Paper Mario will result in a crash. Why or how this happens is still unknown, but there are some theories.

The Wario Apparition
Some theories as to the cause of this anomaly is that the Wario Apparition is crashing Paper Mario, through unknown reasons. It is suggested that upon booting up Super Mario 64, the Wario Apparition hides itself in your N64 and crashes Paper Mario upon booting it up. Why it only crashes Paper Mario specifically is unknown.

Stop N' Swop Bug
One theory as to why this happens is that there was a planned Stop N' Swop between Super Mario 64 and Paper Mario that was soon scrapped. However, they forgot to remove it and when attempting the Stop N' Swop, the game will crash as a result of how unfinished it is.

Intentional Sabotaging
This theory suggests that this is an intentional sabotage by a Nintendo employee who went rouge, who made it so that Paper Mario crashes if you have played Super Mario 64 before as a way to reduce sales on the game, or possibly Paper Mario. If this is true, it did not succeed as both game were found to complete success in sales.

Trivia

 * This was first documented in a Stryder7x video that is now deleted as Nintendo had seemingly silenced him for leaking important Nintendo knowledge.