Excaliber was created by Marv Wolfman and Carmine Infantino.
Major Story Arc
A Sword in Hand
Jason "Slappy" Struthers was a simple, petty thief intent on stealing a sword from the London Museum that was believed to be King Arthur's legendary sword, Excalibur. This sword was however a copy of Excalibur created by the sorceress Morgan Le Fay to use against King Arthur. When Struthers took hold of the sword, he became possessed by one of Morgan's knights. Now calling himself Excaliber, Struthers was used by Morgan to try and steal back her old spell books from Magnus the Magician. Spider-Woman was able to foil Morgan's plan however when she knocked the sword out of Struther's hand, freeing him from Morgan's possession. Struthers was later handed over to SHIELD.
Powers and Abilities
As Excaliber, Struthers possessed enhanced strength, stamina, reflexes, and durability. He was shown to be unaffected by Spider-Woman's venom blasts, he used his sword to knock a train off its tracks, he was able to turn an ordinary police horse into his personal steed, and he could fire off energy blasts capable of stunning his foes.
Struthers only had his powers though as long as he held onto his sword, and would be rendered powerless as soon as he let go of it.