An aquatic scientist scuba diving in Melbourne’s Port Phillip Bay has captured this video of the incredible migration of giant spider crabs.

Sheree Marris, who captured the video, said hundreds of thousands of these giant crustaceans make their way to southern Australia’s shores between May and July each year as the ocean waters cool.

As the name suggests, these crabs are huge. Giant spider crabs are the largest known species of crustaceans in the world and can live up to 100 years, according to the Tennessee Aquarium. Male legs can reach one metre long, or four metres when stretched, according to the South Australia’s Two Oceans Aquarium. Credit: YouTube/The Nature of Science