William "Spike" Pratt, played by James Marsters, is a fictional character created by Joss Whedon and David Greenwalt for the television series Buffy the Vampire Slayer and Angel. Spike is a vampire and played various roles on the shows, including villain, anti-hero, trickster and romantic interest. For Marsters, the role as Spike began a career in science fiction television, becoming "the obvious go-to guy for US cult [television]." For creator Whedon, Spike is the "most fully developed" of his characters. The character was intended to be a brief villain, with Whedon originally adamant to not have another major "romantic vampire" character like Angel. Marsters says "Spike was supposed to be dirty and evil, punk rock, and then dead." However, the character ended up staying through the second season, and then returning in the fourth to replace Cordelia as "the character who told Buffy she was stupid and about to die."

James Wesley Marsters is an American actor, musician, singer, comic book writer, and audiobook narrator.