nail in the coffin
A messed-up mix of phrases that mean someone did something super well, but it probably killed them or someone else. Used when you want to be extra sarcastic.
He hit the nail on the head and got run over by a bus. That was a malaphor for sure.
She did the math problem perfectly and then failed the test. That was a total malaphor.
He won the game and then got kicked out of the club. That was a classic malaphor.