The sighting of an apparently previously unknown species of jellyfish off Cronulla on Australia's east coast is puzzling researchers.
The animal shares structural traits with the deadly box jellyfish that inhabit tropical waters north Down Under, the Sydney Morning Herald quoted biologist Lisa Gershwin, who has described more than 200 species of cnidarians, as saying on Friday.
However, the infamous box jellyfish - the "super-tuned Ferrari of death," as Gershwin calls it - is not actually found in the seas off New South Wales.
"It's a great find," said the expert from Launceston, Tasmania, who has written non-fiction books on jellyfish.
An experienced swimmer, who swims in the ocean off Cronulla near Sydney every day, filmed the unknown species twice in the past week about 800 meters from the shore.
According to Gershwin, it is definitely not the box jellyfish from northern Australia (Chironex fleckeri from the group "sea wasps").
But until the jellyfish is finally identified, it is completely unclear whether it is dangerous or harmless.
What's worrying is the shape of the tentacles, Gershwin explained.
"The dangerous species have flatter tentacles that look like fettuccine." That's the case here, but at the same time the creature also has "gelatinous nodules in its body that look like marbles."
These in turn are associated with harmless species.
The expert is working with the Australian Museum to identify what may be a previously unknown species.
Sea wasps are considered the most venomous animals in the world.
Their stinging cells, attached to tentacles up to three meters long, can kill a human in a matter of minutes.
The animals are transparent, the screen square - hence the name box jellyfish.
They are a major threat along the North Queensland coast, especially during the warmer months.
If you want to be on the safe side, go swimming with a nettle-proof surf, diving or jellyfish protection suit.