According to Australian scientists, a tagged 3-meter-long (9 foot) great white shark was killed and eaten by an even bigger predator, most likely a “colossal cannibal great white shark” Gizmodo reports.

A healthy female great white shark, named “shark alpha” was tagged in Australian waters as part of a large-scale tagging project that set out to investigate the movement of these animals along Australia’s coast. The project, which was recorded by filmmaker Dave Riggs, apparently took place 11 years ago but the Smithsonian Channel is due to air a documentary on this mysterious case shortly. A YouTube snippet of the upcoming documentary, named Hunt for the Super Predator, gives a few details of the bewildering scenario.

According to the video, 4 months after the shark was tagged the device washed up on the coast around 2.5 miles from where it was attached. When scientists retrieved the data from the tag, they were very surprised at what it revealed. The information showed that the device experienced a rapid plunge in depth, descending around 580 meters. However, there was also a concomitant temperature rise, increasing from around 46oF (8oC) to 78oF (25.5oC). The temperature then remained at 78oF for 8 days.

“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 Riggs in the documentary.

Researchers believe that the only possible explanation for this is that it was eaten, as these temperatures are suggestive of the digestive system of another animal.

“The question that not only came to my mind but everyone’s mind who was involved was, ‘what did that?’ It was obviously eaten,” added Riggs. “What’s gonna eat a shark that big? What could kill a 3 meter great white?”

According to Gizmodo, data obtained from further study on migrating larger great whites in the area suggested that shark alpha may have been eaten by another great white. Researchers claim that the body temperatures of the larger sharks were the same as the temperature data that came back from the washed up device.

Furthermore, they suggest that a huge shark estimated to be around 16-foot-long (5 meters) and weigh 2 tons may have had a territorial dispute with the smaller shark, or alternatively was hungry and fancied a nibble.

Although it seems it has been decided that the entire shark was eaten, since the event was not witnessed it remains a possibility that, slightly less dramatically, a chunk was taken out of shark alpha by another animal, which happened to include the tag. Still, it is a pretty fascinating discovery to say the least!

Watch a clip of the upcoming documentary here: