Aussies stumped by bizarre, 'glow in the dark' find in Sydney Harbour

The picture shows a glimpse of what is lurking at the bottom of the Sydney Harbour.

Totally perplexed by his peculiar "glow in the dark" find, one Sydneysider turned to social media in an attempt to figure out what in the world it was.

On Wednesday the Sydney resident came across the "curious" creature which was allegedly covered in slime as it lay against the grey cement near the water's edge at Sydney Harbour. It appeared to be saxophone-shaped, with a stalk and several polyps at the end.

50/50 picture of Sydney Harbour and the unusual find.
The unusual find was covered in slime at Sydney Harbour, leaving many guessing what the creature was. Source: Getty and Reddit / jxckchiboiiz

"Can anyone identify this in and throughout Sydney Harbour waterways?" he asked on Reddit.

Social media respond to the "slimophone"

Many began to wonder and guess what the marine animal could be, with many sharing they too have spotted similar looking creatures in the area.

"I've been curious for years after catching a few myself," one wrote. "This is so interesting! I would definitely get the heeby geebies if I found that on my arm," another admitted.

Expert identifies Sydney Harbour find

The creature spotted by the Reddit user has been identified as a sea pen, an invertebrate marine animal that is usually not found above the water.

"They are relatively common in the eastern part of the harbour, well below the tideline, and so are usually only seen by snorkellers and divers," Dr Shane T Ahyong said.

Sea pens anchored to the sand underwater.
Sea pens stand upright at the bottom of the sea floor and are usually more expanded than the one found by the Reddit user with eight-armed polyps. Source: Britannica

As the Head of Marine Invertebrates at the Australian Museum, he told Yahoo News Australia many of these creatures could be found anchored in the sand at the bottom of the muddy harbour and are a type of soft coral.

Interestingly of all, the sea pen is "bioluminescent", meaning it glows when it is touched, giving it an other worldly appearance.

The light is believed to ward off predators and minimise impact caused by other marine animals while the sea pen's polyps are feeding away. Lucky for the Sydney resident who spotted the creature ashore, the slime it produces is totally harmless, albeit admittedly somewhat unpleasant.

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