Here’s a tip: don’t fight a guy famous for impaling people in the middle of the night. In Sultan Mehmed II’s defence, he didn’t see it coming.
On the night of June 17th, 1462, the Turks were well on their way to Targoviste when Vlad the Impaler launched a surprise night attack with up to 10,000 cavalry. The Night Attack at Targoviste caused chaos in the Ottoman ranks (although many of the casualties were inflicted by confused Turkish units attacking each other.)
Disguised as a Turkish soldier, Vlad snuck into the Ottoman camp with the ambition to kill the Sultan himself. Fortunately for the Sultan, he got lost and hit the wrong tent. The next day, Mehmed’s troops continued their march before stumbling upon 23,844 impaled Ottoman corpses.