monster under the bed
From Wiktionary, the free dictionary
Noun
monster under the bed (plural monsters under the bed)
- Used other than figuratively or idiomatically: see monster, under, the, bed.
- An unreasonable and childish fear.
Usage notes
This is not a fixed expression; one can also say monster under my bed as appropriate, rather than something such as 
my monster under the bed.
Wikiwand in your browser!
Seamless Wikipedia browsing. On steroids.
Every time you click a link to Wikipedia, Wiktionary or Wikiquote in your browser's search results, it will show the modern Wikiwand interface.
Wikiwand extension is a five stars, simple, with minimum permission required to keep your browsing private, safe and transparent.
