I think this is perhaps the Red sea anemone (Actinia tenebrosa), but it looks slightly different, they're usually smooth walled when closed up. (In tidal rock pool)
Rainbow coloured anemone, and I think a yellow Kowhai seed.
Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria. They are named for the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Hexacorallia. Anthozoa often have large polyps that allow for digestion of larger prey and also lack a medusa stage. As cnidarians, sea anemones are related to corals, jellyfish, tube-dwelling anemones, and Hydra.