Sea anemones. Actinia equina

The beadlet anemone, Actinia equina, is a common sea anemone found on rocky shores around all coasts of the United Kingdom and Norway.
It is highly adapted to the intertidal zone as it can tolerate both high temperatures and desiccation. When the tide isn't covering these lovely little animals, they just look like blobs of dark red, brown,green or orange jelly.
Sea anemones have a ring of tentacles surrounding their central 'mouth'. The tentacles have specialised stinging cells that are used to immobilise their prey, (plankton, small crabs and fish) and then the tentacles are then able to move the food into the mouth. The extending tentacles can also be used to catch passing food as it drifts past.