@kaia
Well I'm not @chjara, but I didn't know this expression, and thus did some research for myself. I Found it in an old Israeli newspaper called "This World" (העולם הזה), from Nov' 1981.
It is a mash of Hebrew and German/Yiddish: "-If I'm wrong, call me a kugelager" (קוגלאגר)
It was common that time to put words inside Hebrew, since Hebrew didn't have enough words (Refrigerator="frigider", car="oto" etc.)
Sadly the expression died since, but it's indeed very good