I couldn't help myself but reply with a really long list. It has been a long time since I saw a scary movie, or one that scared me anyway, so the award is gonna have to go to Rec (2007), and prior to that The Descent (2005). Room 1408 (2007) also really scared me at the time, and I discovered when rewatching it last year that there are multiple different endings depending on the version you get.

Other honrouable mentions:

• The Blair Witch Project
• Event Horizon
• Alien
• Aliens
• The Ring
• The Grudge
• Eraserhead while high as a teenager was genuinely traumatising
• Arachnophobia if you are at all scared of spiders
• Jaws when the head pops out
• It (1990)
• 28 Days Later
• 28 Weeks Later when he pops his wife's eyes out
• The Dead Outside is another one that I was too high when watching to remember the plot of, but it was also very traumatising
• Deathwatch is set in the trenches of WW1, and the scariest thing is other people

'

Special shout out to American Horror Story opening credits, which never fail to make me feel deeply unsettled

If I am really honest though the things that scare me the most are movies like Hostel where people are getting tortured ;_; the guy getting his achiles tendon sliced through stuck with me for a very long time