There are some films that make you so frightened you can't watch them unless you have company.
If you put on films like The Ring, The Conjuring, The Shining or The Grudge, chances are you're not going to be having a pleasant night of trying to get to sleep.
One of the most frightening films of all time is John Carpenter's The Thing, which has been denying people of a good night's sleep for years.
This sci-fi-horror is about a shape shifting alien that is uncovered in Antarctica.
The mysterious alien being can take the form and act like any human, which makes it almost impossible to tell who is who.
Upon it's original release, The Thing tanked at the box-office but has picked up a notable cult following over the years.
Today it's considered a horror classic that many consider to be the scariest movie they've ever seen.
The movie's unnerving presence works on two levels. The first is the paranoid atmosphere that the film does so well to build up.
None of the scientists know who exactly the alien is throughout the movie, and neither does the audience.
This keeps the viewer on their toes and leads to many twists and surprises you don't see coming.
The second is that this scariest movie features some of the best practical effects ever seen on screen.
Today most horror films use computer generated effects, and there's nothing wrong with that as many of them look good. There's something about practical effects however that just feels more real in cinema.
The alien effects used in this movie are some of the most creative and genuinely disturbing ever put on the screen.
Many have emulated The Thing's style and production but nothing beats the original.
See the video clip of the scariest movie you shouldn't watch alone
While the film is certainly a cult movie, any fan of horror films has to give it a watch for it's superb use of paranoid tension.
Just watch the infamous blood test scene from this scariest movie below to see how disturbing it really is.
Make sure that when you sit down to watch the whole thing you're not watching alone.