Boogeyman

Boogeymen, boggles or boggarts, are creatures hiding in closets and feeding on childrens' fears. They are first seen in "AAAA Wizardry".

Description
Fairly non-descript, they're known not only to feed on childrens' fears, but also originate them so to have something to feed upon.

"AAAA Wizardry
In "AAAA Wizardry", one gets banished by Megan Yardly, after Harry Dresden indicates it feeds off her children's traumas.