On the Greek Mercenaries Fighting for the Persian Army at the Battle of the Granicus Begging Alexander for Mercy After Being Completely Routed and Him Responding with, "Yeah, I Don't Think so, Guys" and Eventually Killing Them All

Yeah, there are certain people from history that you didn't want to monkey-around with (Genghis Khan, Napoleon, Vlad the Third, etc.) and apparently this Macedonian dude was one of them (in this instance his ire being brought about by a belief that these Thracian and Athenian mercenaries were traitors and thus needed to be executed).