To the casual beachcomber, sea anemones can appear to be simple if slimy amorphous nubs. Yet, these brainless bags of tentacles are teaching complex lessons about the genetic basis of behavior. "Morphologically, they're gelatinous bags of snot," sums up Rick Grosberg, a professor of evolution and ecology at UC Davis. So, he and his Australian collaborator, David Ayre, were surprised to find a complex array of aggressive behaviors exhibited in 148 anemone bouts they set up in the lab. Last year, the researchers reported that some anemones seemed to "remember" an opponent's style and respond faster in a second match. In a paper this summer in the journal Animal Behavior, they report that genetically identical anemones can grow into two types -- warriors, with big weapons, small bodies and small gonads, or reproductives, with large bodies and gonads and few attack tentacles. In the wild, anemones clone themselves and live in genetically segregated neighborhoods; there, anemones living on borders become warriors. In the lab, faced with an enemy (from a different clone), a reproductive anemone begins to transform into a warrior. Also, some anemone clones field much better fighters. A sea anemone fight begins when the feeding tentacles touch. Tempers flare, and an anemone unsheaths its collar of stinging tentacles. The attacking anemone will lunge to strike, landing a thin layer of painful cells that leave scars like cigarette-burns. Defending anemones will bravely tough it out and retaliate or timidly attempt to crawl out of reach.