Wiktionary
n. A creature in United States folklore that may be glimpsed but never seen clearly.
Wikipedia
A hidebehind is a nocturnal fearsome critter from American folklore that preys upon humans that wander the woods, and was credited for the disappearances of early loggers when they failed to return to camp. As its name suggests, the hidebehind is noted for its ability to conceal itself. When an observer attempts to look directly at it, the creature hides again behind an object or the observer and therefore can't be directly seen: a feat it accomplishes by sucking in its stomach to a point where it is so slender that it can easily cover itself behind the trunk of any tree. The hidebehind uses this ability to stalk human prey without being observed and to attack without warning. Their victims, including lumberjacks who frequent the forests, are dragged back to the creature's lair to be devoured. The creature subsists chiefly upon the intestines of its victim, and has a severe aversion to alcohol, which is considered a sufficient repellent. Tales of the hidebehind may have helped explain strange noises in the forest at night. Early accounts describe hidebehinds as large, powerful animals, despite the fact that no one was able to see them.
Usage examples of "hidebehind".
The face, though ugly as a hidebehind made visible, was not so wrinkled and raddled as the shadows of the keep had made it seem.
I was trying to determine the best way of changing into one of those hidebehind things when you interrupted me at the inn.
Bronwyn, who was tired of sleeping, said she would stand watch, though there was nowhere to watch from, since the door would have to be closed to keep out hidebehinds and other creatures and the hut had no windows.
When she stopped, she felt the hidebehinds closing in, menacing her from every side.
What did hidebehinds do to their victims after they made them disappear?
Four men had been attacked by hidebehinds, and two of them were missing in action.
I suggest that we find the Prince and the castle and get indoors before the hidebehinds and monsters come out for the night.