Back in the '80s when I was a kid there was a toy where a monster would pop out and eat people/elves (not sure). As I remember it was a mini scene where something comes out from under a rock. It haunted me for years.
Later as a teen, I saw the DEVILMAN anime movie and it had an intro with fairies flying peacefully over an alien looking forest. Out of nowhere these cute things get eviscerated by all sorts of nasty carnivorous fauna and creatures. It's terrifying and also creeped me out for a while. It reminded me of the toy I am trying to remember.
UPDATE: NAME THAT TRAUMA SOLVED! Special thanks to Chris for solving it with Rocks & Bugs & Things!