The Spanish dancer is one of the largest species and best swimmers of the nudibranchs. Nudibranchs are mollusks who don't have shells in their adult stage. When the Spanish dancer swims, the wide edges of its mantle (the parapodia) are pushed through the water in a graceful undulating movement reminiscent of flamenco dancers. The Spanish dancer is not just known for its dance. It has a reproductive strategy of covering its egg cluster, also called a sea rose, with toxins taken from their venomous food sources in order to protect the eggs from predators.