fabled sword of King Arthur
Excalibur was the fables sword of Arthur Pendragon, King of the Britons. It was sometimes referred to as The Sword in the Stone. As a young man, Arhur proved his worthiness to be king by pulling the sword out of a rock, a feat which no other person was able to do.
When the Ghostbusters followed Sir Trancelot back into the past, they were brought before Arthur by court magician Merlin and his apprentice Fuddy. The King revealed that he had sent several of his knights to Sir Trancelot's Haunted Castle before, but none had returned. He decided that Fuddy would lead the Ghostbusters to the Haunted Castle, since he could not afford to lose Merlin.
Fuddy 'borrowed' Excalibur and almost caused it to be damaged beyond repair while fighting Trancelot's pet, Sparky The Dragon. Luckily, Tracy the Gorilla managed to bend Excalibur back into it's original shape using his great strength. Still, Jake Kong Jr. persuaded Fuddy to tell the truth about takign Excalibur to the King. To reward him for his bravery and honesty, Arthur asked Merlin to make Fuddy a Full Court Magician, after serving as an apprentice for 150 years.
Arthur offered to make Jake, Tracy and Eddie Spenser Jr. Knights of the Round Table, and to make Futura the first woman knight. But when they declined so that they could continue their quest for the missing tablet pieces, Arthur told them to take along Excalibur.
The Ghostbusters eventually travelled back to the dawn of time, where Jake used Excalibur to defeat the Ghost of the Missing Link. In doing so, Excalibur got stuck in a rock and could not be pulled out again, not even by Tracy. Jake then surmised that it had been destiny to return the sword to the same rock from which it would be pulled free by Arthur many centuries later.
Excalibur first appeared in the episode Frights of the Roundtable.