Boris Karloff (1887-1969) was a 20th century British actor recognized as one of the true icons of horror film, and the actor most closely identified with the general public's perception of the "monster" from the classic Mary Shelley book Frankenstein. He frequently costarred with other horror icons such as Bela Lugosi in films like The Black Cat.
Karloff appeared in archive footage in ENT: "Horizon" as Frankenstein's monster. During his career he hosted Thriller (1960-1962), a television anthology series that originally told ordinary tales of crime and mystery, but later became a showcase for Gothic horror stories. Many Star Trek actors made appearances on this program in their early careers, as well as appearing in some of his films.