You can't make this up.

Said of a situation, event, or action that is or seems especially bizarre, surreal, or hard to believe. A piece of metal that had embedded itself in the patient's abdomen from the accident actually deflected the bullet away from his vital organs. I'm telling you, you can't make this up. The guy I'm dating used to be best friends with the brother of a girl I went to band camp with when I was eight years old. Life is wild—you can't make this up.