The flag of the Benin Empire (1440-1897):
That's pretty hard core.
And note that the victim is not only unarmed, but was also merely trying to samba. All that is missing is a cartoon bubble with the victim saying "Ouch" or "Quit it!"
Benin was a little empire located in present-day Nigeria. The nobility which ran the empire were, obviously, very protective of their land and holdings.
In 1897, the tribesmen of Benin killed eight British explorers, along with 243 native carriers, in a massacre that one imagines is much like the flag depiction. Great Britain, of course, wasn't going to take this lying down, and promptly ended the empire by, essentially, burning it down.
So much for the flag.[H/t: Blame It On The Voices]