Sam Kanizay, 16, pulled up sore after playing football on Saturday and decided to soak his legs at Dendy Street Beach in Brighton. Minutes later, he came out covered in blood.
Doctors struggled to explain the teenager's mysterious injuries, so his father Jarrod decided to investigate.
Armed with a fishing net and a slab of fresh meat the following night, he headed back the beach and captured hundreds of the creatures he believes were responsible.
'I caught some bugs overnight over in the bay. I've put meat into a net and they've grabbed on to that like no tomorrow,' Mr Kanizay told Daily Mail Australia.
'We've brought them home and they've just attached themselves to this meat. They've sucked the life out of it - all the blood.
'They're mite type creatures. One would assume these are the bugs that have grabbed on to him in their thousands.'
Mr Kanizay said the bugs have been taken to hospital and tests will be conducted to determine the species.
'What is really clear is these little things really love meat,' he said of a video, which shows the creatures in a tray of water devouring chunks of meat.