King Arthur is the legendary High King of Camelot, England, who because he pulled the enchanted sword Excalibur out of a stone was given the right to rule. He also is a character who appeared in the Smurfs cartoon show Season 9 episode "The Smurfs Of The Round Table". In the episode, he was watching a jousting tournament when his nemesis Morgan le Fey stole Excalibur from him and used its magic to turn him and his men to wax (with the exception of Sir Lancelot, who was shrunk to Smurf size, and Merlin the magician, who was turned into a rock). She then cast a spell on the sun to make it burn hotter so that King Arthur and all of Camelot would melt into nothingness leaving her to rule over England.
The time-lost Smurfs who appeared in Camelot when this happened split up into two groups, one group staying behind to keep King Arthur and his men from completely melting; the other group led by Papa Smurf going with Sir Lancelot and Merlin (still trapped in his rock form) to confront Morgan le Fey and to retrieve Excalibur from her. With Papa Smurf's group succeeding in their quest, Merlin was restored to his human form and so used Excalibur to restore King Arthur, his men, and all of Camelot to normal. King Arthur was so grateful for the Smurfs coming to the rescue of the kingdom that he officially dubbed them "The Smurfs of the Round Table", at a banquet held in their honor.