Divers in Australia have captured rare images of the Pyrostremma spinosum, or pyrosome, sea creature off the coast of Tasmania. It is so rare it has been dubbed the 'Unicorn of the Sea' and can grow up to 30 metres long - the equivalent of two buses laid end-to-end. Its hollow, translucent, cylindrical body is made up of thousands of tiny clones called zooids that pull water through its tubes and feed on plankton before pushing the filtered water back out.
The zooids (pictured above) are each connected by tissue and move as one inside the pyrosome's tube structure and each zooid is a few millimetres in size.
Also called a sea squirt, the pyrosomes are classed as pelagic, which means they are free-swimming and live in open water rather than near land. This means they are rarely spotted and only diving groups are likely to catch a glimpse of the giant creatures.
The long tube consists of a pointed end with a hole on the other that can be as wide as two metres.
Each pyrosome feasts on plankton.
The pyrosome is so delicate to touch one diver is said to have even described it like a feather boa.