For me it was The Lord of the rings, man the fucking uruks, goblins, trolls, nazguls scared the shit out of me as a kid..... So as I got older I rewatched all of them several times
Original 2002 Resident Evil movie. When I was kid I didn't know what I was watching so when the first zombie appeared and attacked I got so scared but still decided to watch the movie to end for some reason.
Actually kind of funny because I decided to watch it for fun like few months ago and it looked so dumb and I was just laughing how stupid it looked but damn was it scary as kid. Maybe reason why even to this day I find zombies kind of scary and overall feel really uncomfortable when playing Cod Zombie for example. I don't know.
Also there is this movie with this giant spiders that would kill humans maybe "Eight legged freaks" can't remember the name and I was so scared going to sleep for like week and still later would sometimes check my room's corner just so there wouldn't be huge spider praying on me
Jeepers creeper 1 and 2 (I watched that movie when I was 8 yrs old in 2007 it had a scarecrow which had ninja blades as weapon and it was in a farm not for animals but for humans he use to eat them and once he captured a bus full of students and he grab a student every time and then fly away then come back pick one)