Battle of Karánsebes
"The troops fired at every shadow, thinking the Ottomans were everywhere; in reality they were shooting fellow Austrian soldiers. The incident escalated to the point where the whole army retreated from the imaginary enemy, and Holy Roman Emperor Joseph II was pushed off his horse into a small creek.
Two days later, the Ottoman army arrived. They discovered 10,000 dead and wounded soldiers and easily took Caransebeş."