Mad's parody of Prince Valiant was hilarious. They changed it to "Prince Violent of Drule" (instead of Thule). Prince Violent was a psychotic heir to the throne of Drule, a northern kingdom. He went about the land exterminating very large numbers of Celts, Vikings, Huns, Saxons, Normans, Franks, Germans, and other unfortunates who crossed his deadly path. His "singing sword" wrought utter mayhem wherever he went, cleaving in twain entire ranks of charging warriors, leaving heaps of dismembered corpses scattered hither, thither, and yon. The narration was also quite interesting. I remember one passage which went...

"Prince Violent of Drule, who aspireth to becometh a knighteth ateth Kingeth Arthureth...rounth...rath...rooth...p'tooie!!!"

He also had a nickname. He was called "Vile" for short. Vile had a lascivious eye out at all times for long-haired maidens in distress and frequently set out to "rescue" them, but usually ended up accidentally killing them in the process, poor fellow! He just wasn't safe to be around.