King Arthur's Knights fighting a rat

The King Arthur's Knights is an unimplemented special encounter in Fallout 2.

This special encounter exists in the game files, but is not obtainable in the game because of a glitch. Using Ctrl-R and selecting the map, the player can enter the map, where Knights and the rat are locked in mortal combat. Each of the Knights, including King Arthur, carry $500 and around 200 microfusion cell ammunition. This is handy for running the Highwayman as each Knight effectively allows you to charge the car fully twice. However, "If you do nothing, the rat will sometimes kill the knights, though they often manage to get in an instant kill critical first."

The cave in the cliff face contains the Holy Hand Grenade, which will automatically kill the rat, for 7,500 XP. Survivors, knights or rat, will remain on the map; neither has anything to say to the player character.

Behind the scenes
It is a reference to the Monty Python's movie Monty Python and the Holy Grail where the Knights, not expecting a challenge from a rabbit until it killed several men, must kill it with the "Holy Hand Grenade of Antioch". Also, when King Arthur was supposed to count to three until detonation, he accidentally counted five and had to be corrected. This is referenced in a Wild Wasteland encounter in Fallout: New Vegas.