Willis Harold O'Brien (March 2, 1886 – November 8, 1962) was an American motion picture special effects and stop-motion animation pioneer, who according to ASIFA-Hollywood "was responsible for some of the best-known images in cinema history," and is best remembered for his work on The Lost World (1925), King Kong (1933) and Mighty Joe Young (1949), for which he won the 1950 Academy Award for Best Visual Effects.