When the Mongol hordes of Genghis Khan were advancing across Asia they used a lot of psychological tactics to gain victory. When they first attacked a village they would kill most of the men, burn a lot of the buildings, and rape most of the women. My intuition says that the term Mongolian clusterfuck comes from the fact that there were inevitably more Mongols than women, thus they would swarm around any woman found and forcibly penetrate any orifice available. If there was not a free orifice, it is said that they would use their daggers to create new ones.
The men whose lives were spared were given horses and told to ride to surrounding villages and spread the news of the invasion. This worked wonderfully, as most people in the surrounding villages quickly ran away upon hearing the news.