A "head case" is Irish slang
for somebody who is nuts/crazy/mad/dangerous/funny. Also popular in Middle America
I am told.
A little bit ooh, a little ahh, a little bit whish-whish-whish.
"Look at yer man about to jump off that skoy-scraper. What a bleedin' head case."
"That Saddam fellah, bit of a head case wha'?"