Also used as an exclamation of
Crapshaith on a bapshaith derives from the Group X usage of Crapshaith, meaning poop/crap/fices stuff.
The term originated from the Bay Area and is most commonly used in the Heart of the Bay aka: Hayward.
"What the crapshaith on a bapshaith"
"You're a crapshaith on a bapshaith"