The Game Over glitch is a glitch in Final Fantasy VI that activates when the player is defeated 52 times in a row on the world map. This will trigger some odd behavior, varying from the game freezing to triggering glitched cutscenes.
The glitch is caused by the game using an event pointer stack while handling the event scripts. One event calls a script as a subroutine and pushes the current event pointer onto the stack. Another event ends the current script, pulls the previous event pointer from the top of the stack and relocates to that address. When the player gets a Game Over, the script that triggers the Game Over screen pushes two event pointers to the stack, but only pulls one. If this is done 51 more times, it will lead to a stack overflow that overwrites the RAM and causes this glitch. If the player enters a location at any time (such as a town), the event pointer stack is cleared.
There is a bugfix patch that players can use to fix it on the SNES version.