A fisherman thought he had caught a rock. He grabbed a prehistoric treasure instead.

A Nebraska man fishing in a tournament got more than he bargained for after casting his line in the Missouri River earlier this month.

Andy Moore was fishing west of Yankton, South Dakota when he grabbed a rock in the water and kayaked out to get a closer look, NBC affiliate WOWT reported.

“I get up and I’m like, ‘Oh wow! It’s pretty cool,” Moore told the outlet.

“I thought it was a big catfish skeleton or a deer skeleton. Something told me to take a picture of that.

Moore shared photos of the object online, WOWT said, and someone reached out to suggest it could be a prehistoric fossil.

The fisherman then contacted a US Army Corps of Engineers biologist, who confirmed to WOWT that Moore’s find appears to be a 90 million year old predatory fish fossil.

“I’m still a bit blown away by it all,” Moore said.

The fossil will no longer be underwater, as it is being prepared for display at the Lewis and Clark Visitor Center in Crofton, Nebraska.