I am new to saltwater and have set up my first full marine tank, with some completely cured/cycled live rock from a quality pet store in town. i have been noticing all kinds of life on/in it, including a brittle star, some kind of tube/fan worms, snails, and just today i spotted something that looked kind of like an armless 6 pointed starfish on my rock. it was about 1/8 to 1/4 of an inch in diameter, and was very flat. I wasnt sure if it was a coral or sponge that i had no noticed before, or if it was a moving organism. Unfortunately before i could find my iphone to get a pic, it had moved out of site. Anyone have any idea what it is? Ive googled it for about an hour with no results.

