The horror that used to be shown during the early years of 
VHS was astounding. Creepy visuals and sounds mixed to create a sense of dread and 
horror that is still palpable today.
One example is The Secrets of the Phantom Caverns:
My brother had 
nightmares from the trailer alone and refused outright to see it. The film is relatively 
tame - it seems some albinos (people in bad makeup) live underground with hand 
puppets that stick out of fake rock walls. And stars Timothy Buttons as Major Stevens! (Who?)
The Adventures of Buckaroo Banzai Across the 8th Dimension was 
another oddity in terms of trailers:
A disparate group of oddly dressed men 
(including Jeff Goldblum as a cowboy{!}) assemble in an urban drain, inter cut with bizarre imagery of otherworldly beings mixed with grunting electro pop synths. It produced a disorientating and undeniably disturbing experience for this ten year old!