Marine biology student recalls terrifying shark attack that cost him his leg — and how he managed to escape: video

Shocking video shows the moment a marine biology student emerged screaming from the water after losing a leg in a shark attack.

Matteo Mariotti, a 20-year-old Italian studying in Australia, posted harrowing footage that shows him struggling to reach the surface as a shark tries to pull him under the water at a remote beach off the coast of Queensland on Friday.

After a lengthy scramble, he emerges screaming for help as he desperately tries to reach a friend on the shore.

That friend, Tommaso Agosti, eventually reaches him and pulls him out — as a cloud of blood covers much of the water. 

Agosti then yells for help as he attempts to calm his friend’s breathing and staunch the bleeding.

After screaming for a belt, Agosti made a makeshift tourniquet and “carried me on his shoulder” to where an am balance met them, Mariotti wrote in an Instagram story.

However, they were unable to save one of the student’s legs, which was amputated below the knee, according to an online fundraiser he linked to.

Still, “I never thought I’d survive that monster,” he wrote of the shark attack, assuming he would have to “say goodbye.”

“Tommaso saved my life,” he said of his pal.

He also attributes his miraculous survival to his late grandfather, who passed away just one day before the attack.

“I no longer have a leg, but I’m alive, my grandfather protected me,” Mariotti told L’Unione Sarda from his hospital bed.

Mariotti was taking a temporary study break on the beach to find solace amid his grief for his grandfather Friday afternoon when he decided to go for a swim.

He said he brought a small camera with him to film the fish, “but after a few steps in the water, I felt a terrible pang in my foot.”

Soon, the pain crept up his entire leg.

“The shark began to drag me out to sea, until at a certain point I managed to grab its head with my hands,” Mariotti recounted.

“I struggled to widen that big mouth and freed my leg, even though I understood that from the knee down there was nothing left.”

He then made his way to the shore.

“I was screaming in fear that the shark would reach me, I was screaming for help from my friend Tommaso, who was on the beach.”

A GoFundMe raised more than $40,000 in just one day.

“Matteo will need support and very expensive medical care to get back to living his best life as a 20-year-old, and we are determined to do our utmost to help him,” wrote the organizers.