Sea pens on sand, in current, off the East side of Santa Rosa Island. The east side of the island is sheltered, but most of the bottom is sand until quite close to the rocky shore. Stiff currents can make it tough to reach the fun spots.
A rock covered with worm tubes, near Underwater Island at Anacapa. Humans once spent most of their lives in a small community, with only a few members; as do these tubeworms today.
A nudibranch (or, more likely, two) left these spirals of eggs on the stem of a sea palm at Santa Rosa. Nudibranchs are hermaphroditic, so perhaps both sprials have the same parents.