I think this is a bit of an obscure one.
At some point in the early â€˜90s, when I was about four or five years old, I saw a cartoon on Children's BBC (I think) called STOPPIT AND TIDYUP. Or rather, I saw about ten seconds of it, because after that I ran away screaming. I can't put my finger on exactly what it was that scared me, but there was something about the character designs that I found unbelievably disturbing.
I know it was a five-minute short, because that's what my mother told me in order to get me to come downstairs from my room ten minutes later, but apart from that, I know next to nothing. I remember that, for years afterwards, I was always a bit nervous whenever I was watching that channel, all prepared to bolt in case it came on again. Once or twice, it did, but I always managed to get away as soon as the title sequence started, so I never saw any more of it. I suppose I could go to the show's Wikipedia page to look up some information on it, but… there might be pictures.
Anyway, here's the strange part- from that day to this, every time I've mentioned STOPPIT AND TIDYUP to a group of people my age, someone has always said, "Oh, God, that terrified me as a kid!" And that's the only thing that they can remember. As far as I can gather, this show's entire legacy was to disturb an entire generation of four-year-olds. And considering that, a few years ago, I found out that it was by the same people who made THE TRAP DOOR (which is essentially cosmic horror for tinies), I'm starting to suspect that they did it on purpose.
(Also, when I was six, my Year One class were shown the cartoon version of ANIMAL FARM. I'd write this off as the teachers being a bit distracted and not reading the blurb, but then they showed it again two years later- both times in a double-bill with CHARLOTTE'S WEB, strangely enough. Apparently they were going for a "farm animals in peril" theme. Anyway, for about ten years afterwards, ANIMAL FARM was still the scariest film I'd ever seen. It kind of spoiled me for horror movies.)