Spectators' close encounter with barnacles
An enormous mound of moving crustaceans has been washed ashore on a Gower beach.
Spectators gathered at low tide to examine the thousands of Goose Barnacles on Oxwich Beach.
Rebecca Porter said they were moving and opening like "a large living sea monster".
She said, "The stalk on which the puffin-shaped head sat on was soft and rubbery and moved like a snake."
"They appeared to be attached to a piece of drift wood but it could hardly be seen as it was densely covered with these huge barnacles that opened and closed thrusting out fronds like uncurling ferns," she said.
The barnacles are normally found in large groups in quite deep water and feed on plankton and small crustaceans, but are generally blown in during stormy weather.
Just part of the mound of barnacles
Tim Hall is Marine Campaigns and Advocacy Officer for Wildlife Trusts Wales said, "They also like driftwood, hulls of wrecked ships, etc and this is when most people see them after they are washed ashore."
"The fronds described are used for feeding (there are six pairs of very thin, feather like cirri) and I imagine that hundreds of those moving in and out must be quite a site, hence looking like a large sea monster."
"Just another example of the wonderful wildlife that thrives in our seas and certainly something different for the holiday makers in Oxwich bay to see."
Dr Nova Mieszkowska is a research scientist with the Marine Biological Association of the UK, which records sightings such as this one.
She said that when feeding these creatures can look almost as if they are waving and so give the impression of movement, which may have been what visitors to the beach noticed.