Scientists who had affixed a tracking device to a 9-foot-long great white shark are now scratching their heads, wondering what kind of “mystery sea monster” could have possibly eaten their shark.

The great white, which had been tracked by Australian researchers for weeks, suddenly went missing — and then its tracking device was found on a beach, United Press International reported. Data on the device revealed the temperature of the shark went up and down in quick succession, leading scientists to believe it was being digested by another animal.

So now they’re thinking it was eaten by “a colossal, cannibal great white shark,” UPI reported. But they’ve not seen such a beast — and they’re mystified by what the ocean depths might actually contain.

“When I was first told about the data that came back from the tag that was on the shark, I was absolutely blown away,” said filmmaker Dave Riggs, in a new documentary about the shark for the Smithsonian Institute’s “Hunt for the Super Predator,” based on the Australian film, “The Search for the Ocean’s Super Predator,” UPI reported.

He went on: “The question that not only came to my mind but everyone’s mind who was involved was, ‘What did that?’ It was obviously eaten. What’s gonna eat a shark that big? What could kill a [9-foot] great white?”

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