Austria during 1787, or as they were known at the time the Hapsburg Empire, was a close ally of Russia. This was mostly to fight a common foe: The Ottoman Empire. The Turks were attempting to expand heavily into Europe and in 1788 there was fierce fighting in current day Romania, over who would control the Danube River. This was a key supply river at the time and would allow either force to easily reinforce. There were many bloody battles during this time, yet mostly this war is remember for the infamous events that took place in Karansebes which resulted in the death of 10000 soldiers.

I know what you are thinking, this was a war and there is bound to be a high amount of casualties. However, these soldiers all perished as a result of friendly fire! In fact, the Turkish Army had not even arrived at Karansebes before Austrian artillery was blowing their own troops to smithereens! It may be one of the most embarrassing military failures, and why it largely went undocumented until around 40 years later.
Of course, friendly fire does happen, it is one of the sinister consequences of war. In the heat of the moment, sometimes vital communications are lost and mistakes happen. Yet never has it resulted in such high casualties. So how did the Austrian Army essentially defeat itself during the 1788 Battle Of Karansebes?
One thing we have to note is that the Austrian Army was made up of Austrians, Czechs, Germans, French, Serbs, Croats, and Polish. This made communication a nightmare for officers, as no one spoke the same language, and resulted in an army that was poorly organized. And it was this language barrier that was their downfall. During the night some Austrian infantrymen and cavalrymen got into an argument over some alcohol that had been offered by some passing Gypsies. Of course, every Austrian wants to drink some Schnapps. Especially when going to battle!
The argument turned ugly and a shot was fired, suddenly the main camp was shouting “Turks, Turks!” and utter chaos ensued. Austrian officers were shouting “Halt, Halt!” in German, trying to restore order but the majority of the soldiers did not speak German and believed they were hearing the Turks screaming “Allah Allah” as they attacked. Suddenly everyone was shooting anything that moved in the darkness, however, the worst was yet to come. A commander believing the Ottoman cavalry was reaping havoc upon the camp decided to bombard his own men with artillery fire! This is what undoubtedly caused the enormous casualties: 10000 Austrian soldiers dead.
The Turkish Army? Well, they did not arrive until 2 days later and found to their delight that the town of Karansebes had no defenses.