Australian fisherman Trapman Bermagui fished out the severed head of a massive mako shark from the depths of ocean off the coast of New South Wales in Australia.

It begs the question: what animal is big and vicious enough to bite off such as large shark's head?

Decapitated Shark Head Found In Australia's Waters

Bermagui, also known as Jason, posted photos and a video of the severed head on Facebook, Instagram, and YouTube, quickly becoming viral and intriguing people from all over the world.

A group of fishermen including Bermagui were trying to haul in a smaller shark when the mako shark ate it. Then, as they were trying to catch the mako, another creature attacked and decapitated the animal, according to the description on the fisherman's YouTube channel.

"We didn't see what ate the mako," Bermagui tells CNN, adding that the entire shark weighed at least 550 pounds (250 kilograms). On its own, the head weighed about 220 pounds (100 kilograms), according to the fisherman.

Then, when Bermagui and the rest of the group cut open the head of the mako shark, they discovered another surprise: a bill of a marlin embedded on the shark's throat. It's been healed over and has likely been there for many years.

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A post shared by Trapman (@trapman_bermagui) on Mar 29, 2019 at 2:03am PDT

What Ate The Mako Shark?

Looking at the grisly sight of the mako shark's head makes it easy to imagine a monstrous megalodon-like creature lurking under the waters of Australia.

The truth is likely not as cinematic, yet no less awe-inspiring: probably a tiger shark, Bermagui says, which is an animal that is plentiful in the surrounding waters. Other types of shark are also possibly the culprit.

Some experts say that the mako shark seems to have been killed off by more than one attacker.

"Even a huge great white shark wouldn't cut a large mako in two pieces in one bite," Johann Mourier, shark scientist and behavioral ecologist at UMR MARBEC in France, points out to IFLScience. He adds that the photo shows several big bites rather than just one huge chomp. "[It] seems to be a big shark with multiple bites [from] multiple sharks."

Since the mako shark was already caught on Bermagui's hook, the creature was especially vulnerable to attacks, according to Clive Trueman of the University of Southampton in the United Kingdom.

"Once hooked, the struggles of a shark (or other fish) are likely to attract sharks and other predators," Trueman explains to CNN, saying that fish that usually can't attack the huge mako will be able to bite into the animal once it is hooked and helpless.