On our recent visit to Hornby Island, we were amazed by how many jellyfish were on the beaches and rocks. They had beautiful and rich coloured patterns, were mostly around 15″ across, though one was about 20″. We think they are the Lion’s Mane jellyfish. Note the crab inside the third one. The last photo shows a small one in a tidal pool, I don’t know if it’s the same species.