Sea Anemones

Sea anemones are a group of predatory invertebrates related to corals and jellyfish. Most sea anemones are a single polyp that typically attaches itself to the substrate (usually a rock, but can also be in the seafloor sediments). Their body consistes of a trunk topped with a ring of tentacles surrounding the oral disk, with the mouth in the center.

And yes, sea anemones are named after the terrestrial flower, anemone.