I can see parents being scared by the very premise of Season 1. But Imma go with 4

I wasn't scared of any of them but s4 i guess was the creepiest compared to the other seasons

Well when I seen S1 I had no idea what the hell was going on, my only knowledge of the show was through Dead by Daylight. Season 4 was more graphic, but I wasn't really scared

Season 4 in general, but the Demodogs hunting down Bob at the lab in season 2 was the most horrifying scene of television I’ve been watched.

Season 4 is probably the scariest out of all of them, but I would like to point out in Season 2 that Bob’s mutilation and Will’s possession were very dark with their own notable, frightening moments—thus, the reason why I put Season 2 as a close second. Season 3 was the least scariest season for me.

All of them unnerved me but it's Vecna's kills that actually scared the hell out of me.

None of them scared me, but the way we saw Vecna's victim's die was probably a tiny bit scary for me, so I'd have to go 4.