The "Bogeyman" is a nasty and loathsome creature, though they are for the most part harmless. They begin their lives as a paper-thin larva known as a "rug-bug", so called because they prefer to hide underneath rugs for protection. Rug-bugs are about the size and shape of popsicle sticks.
During this stage in their life, the rug-bug permanently anchors itself to the underside of the rug, feeding off of any dust and scraps that are carelessly swept beneath its new home, as well as its own moltings. The rug-bug quickly grows to the shape and size of its rug in as little as two weeks (though ones that nest under larger room-sized rugs can take a month to grow or more), developing eyes, limbs and a hard exoskeleton, maturing into a full-grown Bogeyman.
A full-grown Bogeyman no longer sustains itself on dust and decay, or any physical matter at all- rather, they feed off of human emotions, with fear being the easiest one to obtain, which is why they terrorize children at night (though there are several accounts of them frightening children during the day, most often in the bathroom).
Bogeymen reproduce asexually via tiny green pods that grow in the two nostril-like portals in their face, which they will extract with their finger and silently place inside a child's ear, hence their name "Bogeyman". The brain waves emitted from having a nightmare causes the pod to hatch, allowing the larval rug-bug to scurry off to rugs unknown.

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Inspired by Terry Pratchett's Discworld books as well as Stephen King.