A good horror performance has the ability to scare an audience, but a truly exceptional actor has the ability to scare themselves.

Boris Karloff, a man of both talent and merit, made his mark on film history by playing a collection of horror antagonists that terrify viewers to this day. Karloff is perhaps best recognized from his work in Frankenstein (1931), where he played the titular monster. It was a role he would later reprise in films like Bride of Frankenstein (1935) and Son of Frankenstein (1939).

The process of becoming Frankenstein’s monster was a laborious one, complete with heavy special effects makeup to truly make the film believable.

Of course, perhaps this job was done a bit too well, as Karloff stated that when he first caught sight of himself as the Monster, he sent shivers down his own spine.

“I’ll never forget the shock when I looked in the mirror and saw myself,” said Karloff during an interview with the Hartford Courant. “I’d worn makeup before, but never anything like that. It gave me the strangest, sickest feeling - as though I’d permanently changed into something hideous.

The experience was frightening enough that it actually continued as the film went into production. Karloff grew weary of his own face.

“When I wear this makeup, I try to look in the mirror as little as possible,” said the actor. “I can’t get over the feeling I’m actually changing into these things. It makes me feel morbid and depressed. The first night after I’d played in Frankenstein, I dreamed the monster was chasing me. I was drenched in cold sweat and groaning.”