MELBOURNE, Australia -- A teenager who just wanted to relax his legs at a Melbourne beach but emerged with his feet covered in blood has stumped marine experts, but one biologist is convinced the culprits were tiny scavengers.

Sam Kanizay's legs felt sore after playing a game of football on Saturday, so he decided to soak them at the beach. About 30 minutes later, the 16-year-old walked out of the water with his feet and ankles covered in what looked like hundreds of little pin holes that were bleeding profusely. Upon returning home, his parents promptly took him to the hospital.

Kanizay's father, Jarrod, said hospital staff had no idea what kind of creature could have caused the injuries. So Jarrod went back to the beach the following night with a pool net full of meat and captured the animals he believes could have been responsible. He took a video of dozens of the tiny bug-like creatures chomping on the chunks of meat.

"What is really clear is these little things really love meat," he said.

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Jeff Weir, executive director of the Dolphin Research Institute, believes the teen may have been attacked by parasitic crustaceans called amphipods, which usually eat decomposing plant and animal scraps.

But Thomas Cribb, a parasite expert from the University of Queensland, said it would be very unusual for amphipods to cause such extensive bleeding.

"It's not a parasite I've ever come across," he said.

But in remarks published Monday on Australian news website news.com.au, associate professor Richard Reina, with Monash University's School of Biological Sciences, said he was convinced amphipods commonly known as "sea lice" or "sea fleas" were the culprits behind the attack.

"I think it's very rare," Reina admitted to the website, but he said Kanizay was likely chewed up so badly because he stood still for an extended period of time.

"He probably thought the pins and needles he described was the cold and didn't realise there were crustaceans chewing on his feet," he said.

In this image made from video, Sam Kanizay, 16, holds a jar with creatures in it as he speaks from his bed in a hospital where he was being treated for bites to his feet, in Melbourne, Australia, Aug. 7, 2017. AP

Reina told news.com.au that sea lice don't generally travel in a large group, but that once a small number drew blood, it would have attracted all the others.

"They are very good at finding food," he said of the scavengers. "It looked really bad in the photo, his feet looked like they went through a mincer, but it's a superficial injury and more like a graze than anything else... I would expect and hope he will recover pretty quickly."

Kanizay was still hospitalized on Monday, but had been taken off antibiotics.