4. The Secret of N.I.H.M. (1982)
The actual "secret" of N.I.H.M, I think, is that it's hiding the fact that it wants to traumatise you forever, which is what it did to me when I stumbled upon a VHS copy at some point in the '90s. This one comes from the mind of Don Bluth, who you'll also know as the man behind
An American Tail (also kind of disturbing, come to think of it) and a bunch of other darkly-paletted animated movies pretending to be for kids. Anyway, here Bluth adapts an obscure novel about a field mouth who has a sick son and needs to shift him in time for plow season, 'less they both die horribly. The bringer of death here is the tractor, which is depicted as one of the most horrific objects known to mankind. Seriously. Even knowing that a tractor wasn't a threat to me,
N.I.H.M. assured that a visit to the farm would never be the same again. Then there's the rat clan of the movie's title, all of whom have been used for drug testing. It's one huge, 90-minute long nightmare.