A lowly rodent who, out of desperation, has learned to live alongside man by occupying one of our less-than-ideal structures, the outhouse.
Eternally mocked by the rest of the animal kingdom for it's choice of habitat, it passes through life barely noticed by man except in this phrase: "Poorer than a shithouse mouse"
Clearly indicating that the individual described does not even possess the meager funds required to reside in an outhouse.
After being denied $20 from the ATM machine for lack of funds: "Damnit, I'm poorer than a shithouse mouse"
An incomprehensibly crazy person.
NB: Not used to describe a spell of psychotic behavior. A shithouse mouse is permanently insane.
Used as a comparative standard, usually vis-a-vis actual insanity.
The term originated as a more mellifluous alternative to the term shithouse rat
; e.g., "as crazy as a shithouse rat."
Did you see Shavonne flip out and claw the skin off Joey Bag's arm last night? I'm glad you dumped that psycho, she's crazier than a shithouse mouse!
I saw the born-again Christians picketing at the train station again yesterday, every one of them crazier'na shithouse mouse.
An exclamation of frustration
I guess my computer has decided to stop having a "turn off" option. Well, shithouse mouse, I'll just have to let the battery run down.