A swarm of a new variety of deadly box jellyfish was recently spotted off the coast of Pilbara in western Australia.

Nearly 100 of these soft, white, and translucent creatures emerged from the waters 1,530km north of Perth, stunning marine biologists because it’s likely a new kind.

The jellyfish typically found in the northern waters are characterised by their rounded and cube-shaped bodies with lengthy venomous tentacles, and scientifically known as chironex fleckeri.

Dr Lisa-ann Gershwin, one of Australia’s leading jellyfish taxonomists, told ABC News: “This one we’ve thought about for a while is probably new to science.” It has not yet been named and classified.

Dampier port worker, Ben Walkington, said he did see box jellyfish while growing up but this is for the first time in a long time that he spotted this kind.

“It’s not ideal,” he told ABC News. Box jellyfish are among the planet’s deadliest invertebrates. Nearly 80 people have died from box jellyfish stings in Australia since records began.

The kind that washed up in Pilbara are likely different from the box jellyfish seen in the waters of Northern Territory and Queensland, Dr Gershwin said.

In March 2021, an Australian teenager became the first person to die from a box jellyfish sting in 15 years. It was the first recorded fatality since 2006.

Box jellyfish venom contains toxins that attack the heart, nervous system, and skin. Each of its tentacles, which can grow up to 10 feet in length, contain about 5,000 stinging cells.

Their sting is so painful that swimmers have been known to go into shock and drown or die of heart failure before reaching the shore.

Commonwealth Scientific and Industrial Research Organisation’s scientist, Dr John Keesing, told the ABC: “They do occur as far south as Exmouth, but to get reports of large numbers of them is unusual.”