What the heck is this giant dinosaur-looking shell found in Argentina?

Jose Antonio Nievas was out for a stream-side walk on Christmas Day when he stumbled across a shell that looks straight out of Jurassic Park.

After partially digging it out of the mud, the Argentine rushed home to tell his family about his discovery. “At first I thought it was a rock or a car tire,” he told Argentine newspaper La Nacion.

“When he came back he said, ‘Hey, I just found an egg that looks like it came from a dinosaur,’” his wife, Reina Coronel, told the news agency AFP. “We all laughed because we thought it was a joke.”

But was it?

Argentine paleontologists say it’s probably the shell of a glyptodont, a giant prehistoric armadillo that might have looked something like this:

“There is no doubt that it looks like a glyptodont,” Alejandro Kramarz, a paleontologist with Argentina’s Bernadino Rivadavia Natural Sciences Museum, told AFP. “The animal became extinct thousands of years ago and it is very common to find their fossils in this region.”

The prehistoric mammals had big round shells and were believed to weight up to a ton.