The Hideous Sun Demon (sometimes billed as The Sun Demon, or in the UK as Blood on His Lips) is a 1958 American science fiction horror film produced, directed, and cowritten by Robert Clarke, who also starred in the title role. It also stars Patricia Manning, Nan Peterson, Patrick Whyte, and Fred La Porta. The film focuses on a scientist (portrayed by Clarke) who is exposed to a radioactive isotope and soon finds out that it comes with horrifying consequences.