If we’re talking about games then I can remember being terrified of the first zombie encounter in Resi 1. The way he slowly turned his head gave me the heebeegeebees (I have no clue how to spell that word).
If we’re talking outside of games, there was this tv channel (I was about 4ish at the time, I remember because it was in the first house I lived in) that showed cartoons early in the day. But everyday at like 1 minute to 12 noon, they’d stop whatever they were showing and they’d show this countdown clock/timer thing that counted down til the news was shown. For some reason the timer freaked me out, I think it was because of the silence, my mother would always be outside doing something and I’d be by myself in the sitting room and all of a sudden when the silence came I’d be very aware of how alone I was while also feeling like I was being watched, I’d leave the room whenever it came on after a while.
So I was terrified of a countdown timer as a child.