So, if I recall correctly, the enemy had 3 HP left.
I had a buffed up Unlikely Hero attack a Court Jester, which naturally triggered my Bloodsinger and Blood Obelisk to deal damage to the enemy.
Then this popped up:
Game proceeded fine after I reloaded the client. Opinions may vary, but I think it’s awfully cheeky of the AI to crash the game because they’re afraid to lose.