Was it part of a super-secret government program to study the effects of caffeine on horseshoe crabs? Or maybe it was an unadvertised promotional giveaway that went terribly wrong?

Either way, beachgoers found a lot more than shells and seagulls in Melbourne, Florida, Tuesday.

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Hundreds of cans of coffee washed up onto Melbourne Beach, and the Coast Guard doesn’t have any idea where they could have come from.

More than two dozen cargo containers headed for Puerto Rico fell off a ship two days ago, but the Coast Guard has not found any connection between that and Tuesday’s coffee surprise.

Cans of coffee on the beach didn’t last long, said Christopher Sybo, who was staying in a hotel overlooking the beach.

“I noticed something yellow all over the shore,” he said.

When he investigated, he found can after can of sealed coffee grounds. He was one of the first people to see the coffee spill, but he was quickly joined by others.

“I took two cans as a souvenir, at first, just something from a shipwreck,” he said. “It wasn’t long after that that more and more people started coming and grabbing cans.”

The cans were scooped up by souvenir collectors and coffee drinkers alike within a couple hours. The Coast Guard is still investigating where they may have come from and what impact they may have on the environment.

Sybo will be heading back home to Pittsburgh with a great vacation story, “and a couple cans of coffee too,” he said.