(as) crazy as a bedbug

(as) crazy as a bedbug

Insane. Often used jocularly. Primarily heard in US. Don't leave me alone with Uncle Stu, he's crazy as a bedbug!
See also: bedbug, crazy
Farlex Dictionary of Idioms.

crazy as a bedbug

AMERICAN, INFORMAL
If you describe someone as crazy as a bedbug, you mean that their behaviour is very strange or silly. By now she'd concluded that Peters was crazy as a bedbug. Note: Bedbugs are small wingless insects that live in beds and bedding. They feed by biting people and sucking their blood.
See also: bedbug, crazy
Collins COBUILD Idioms Dictionary, 3rd ed.
See also:
  • crazy as a bedbug
  • bedbug
  • crazy as a loon
  • (as) crazy as a peach-orchard boar
  • peach
  • orchard
  • boar
  • loon
  • crazy in the head
  • crazy as a betsy bug