The typical response of Asterix and Obelix to the idiotic, arrogant or pointless behaviour of their Roman adversaries, especially Julius Caesar. Typically said while circling the finger next to the ear to indicate insanity and cupping the hand near the mouth as though whispering.

Variations include:
I went to Rome recently and had the opportunity to utter this phrase many times. Tick one more off my wish list!

for The Oolong Man