are they sea anemones? Every British beach I went to as a kid had those. When the tide comes in they open up and send out fronds that sting tiny marine creatures that they eat. You could put a child size little finger in the fronds and feel it tingle
Neurothing •
https://it.wikipedia.org/wiki/Pleurobrachia_pileus
Pleurobrachia pileus - Wikipedia
Contributori ai progetti Wikimedia (Wikimedia Foundation, Inc.)Nick Dunlavey •