From _Monty Python and the Holy Grail_; uttered by Python fans when someone unwanted or unliked is descending on them. In the film, the unwanted people were repelled by hurling cows at them. Example: Oh, no, here comes Rosie; chercher la vache!
CHERCHER LA VACHE
Meaning of CHERCHER LA VACHE in English
Slang English vocab. Английский сленговый словарь. 2012