I think I’ve just stitched together an idea for an bizarre monster/villain. The components of the idea are the ““Psychophagers[](
https://orionsarm.com/eg-article/4703c108c90f5) from the Orion’s Arm world-verse, and the ““Shield[](
http://artemisfowl.wikia.com/wiki/Shield) cloaking ability used by fairies in the
Artemis Fowl novel series.
Essentially, imagine a cyborg, who’s augmented heart (or more than one heart) beats so fast, that their entire body vibrates out of the visual perceptions of the naked eye, leaving nothing left to see but a faint shimmer where they’re standing.
Also, in the
Artemis Fowl series, it’s explained that certain species of animals, like rats or some monkeys, can see through the “shield” vibration-cloak spell, because those animals’ eyesight can catch more frames-per-second than humans (& fairies).
So, imagine a
Terminator-style(The Terminator 1984: Final Scene 4K [Full Version]) cybernetic assassin (or
Umbrella-style Tyrant mutant) set within a scifi-themed MLP-verse, that can vibrate out of sight of it’s prey, but because the world Equestria is in has different sapient species such as griffons, dragons, changelings, subspecies of equine, etc,
the monster-villain would have to choose which species to hide from while stalking.
[ BlueLink Warning: Nightmare Fuel ]
It kinda reminds me of the subjectively-invisible entity from
It Follows(It Follows [2014] - The arrival of a tall man).
:P