A 9-foot-long great white shark that was fitted with a tracking device was eaten by a mysterious underwater beast, Australian scientists say.

The female shark was tagged off the coast of Australia as part of a program to track the species and better understand their movements, Examiner.com reported. The incident apparently occurred 11 years ago, but a documentary on the mystery titled "Hunt For the Super Predator" is to air on the Smithsonian Channel on June 25.

After four months of tracking, the device was found washed ashore on an Australian beach, 2.5 miles from where the shark was tagged. Data from the tracking device indicated that the great white shark- considered to be at the top of its food chain- had been swallowed by an unknown predator.

"When I was first told about the data that came back from the tag that was on the shark, I was absolutely blown away," Dave Riggs, a filmmaker who documented the tracking program, said in a clip from the documentary, according to Examiner.com.

According to the tracking device, the shark, nicknamed "shark alpha," was swimming at a depth of 1,900 feet off Australia's continental shelf when a "huge temperature change" occurred.

The device showed a rapid increase from 46 degrees Fahrenheit to 78 degrees. The only way that could happen is if the shark was inside another animal, scientists said.

"The question that not only came to my mind but everyone's mind who was involved was 'what did that?' " Riggs said according to Examiner.com "It was obviously eaten. What's gonna eat a shark that big? What could kill a [9-foot] great white?"

As it turns out, the wild water beast that consumed the great white shark was a "colossal cannibal great white shark," scientists said according to Gizmodo.com.

Scientists are not sure why the shark consumed a fellow shark. One theory is that the colossal shark, said to be 16-foot-long and weighing over 2-tons, had a territorial dispute with the smaller one.

Or the larger shark could simply have been hungry, scientists said.