Mark Hamill (born September 25, 1951) is an American actor and voice artist. He currently plays Armin Zola, Ox, and Nightmare on Ultimate Spider-Man. He is known in the Marvel Animated Universe as Hobgoblin on Spider-Man; Maximus, Sentry, and Triton on Fantastic Four; and Gargoyle on The Incredible Hulk. He also played Oiler on Ultimate Avengers II, Red Skull and Chthon on The Super Hero Squad Show, and Klaw on The Avengers: Earth's Mightiest Heroes. He is best known for his portrayal of Luke Skywalker in the original Star Wars trilogy and as the voice of the Joker in the DC Animated Universe.