A dinosaur bone from a 250-million-year-old Pliosaur
A dude named John Lambert was fixing his fence, when he saw an unusually large bone sticking out of the ground in Ipswich, England. He thought about contacting a museum, but then put the bone in his shed instead. For 16 years.
Finally, he decided to take it to an expert, where they confirmed that it was one hell of a bizarre find, especially since it was the bone of a water-dwelling dinosaur, found on land.