In “The Dark Half,” Thad Beaumont writes under the pseudonym George Stark.
Thad Beaumont is a literary novelist whose serious books sell poorly, but he achieves commercial success by writing violent crime thrillers as George Stark. The pseudonym becomes public after a journalist exposes Thad as the author behind the popular Stark novels. Thad and his wife then stage a mock burial for George Stark, symbolically ending the alter ego’s career.
That fictional funeral becomes the supernatural turning point. George Stark appears to emerge as a physical being and begins murdering people he believes helped expose or destroy him. The character embodies the darker, more violent side of Thad’s creativity and personality, making the pseudonym more than a professional disguise.
Richard Bachman is a common alternative in trivia because Stephen King used that name for several novels in real life. Bachman is King’s own publishing pseudonym, not Thad Beaumont’s. John Swithen was another name associated with King, but neither is the answer to this question. George Stark is the canonical pseudonym in the novel.