Actinia equina carries a ring of blue structures called acrorhagi at the top of its column, just below the tentacle crown. They are loaded with a distinct type of stinging cell used only against other anemones.
When two anemones make contact, the aggressor inflates an acrorhagus, applies it to the opponent's column and leaves behind a patch of stinging tissue that continues to burn the tissue underneath. The recipient typically detaches and creeps away, and repeated bouts over hours can decide which animal keeps a favourable spot in a tide pool. Individuals of the same clone do not attack one another, so on some shores the pattern of fighting maps onto genetic identity.
Beadlet anemones also brood. Juveniles develop internally and are released through the mouth as small but fully formed anemones, sometimes in considerable numbers, which is unusual among anemones and is why small individuals often cluster near a large one. The common assumption that an intertidal anemone is a passive filter feeder underestimates a predator that hunts, fights and defends ground.