William Horace Marshall was an American actor, director and opera singer. He played the title role in the 1972 blaxploitation classic Blacula and its sequel Scream Blacula Scream (1973), and appeared as the King of Cartoons on the 1980s television show Pee-wee's Playhouse and as Dr. Richard Daystrom on the Star Trek television series. He was 6‘5” tall and was known for his bass voice.

Blacula is a 1972 American blaxploitation vampire horror film directed by William Crain. It stars William Marshall in the title role about an 18th-century African prince named Mamuwalde, who is turned into a vampire by Count Dracula in the Count's castle in Transylvania in the year 1780 after Dracula refuses to help Mamuwalde suppress the slave trade.