They have homing ability, so they're always in the same spot when I go by. Maybe that shouldn't impress me so much, but it does. You can see that I didn't give any thought to brightness, unfortunately.
Sure seemed like a limpet, but couldn't find anything about those nodule growth things...
Shallow water, shell raised to go over barnacular obstructions.
Maybe ten days later, and here they are, all describing the very same constellation as before.
Shallow water, which you should have guessed if you see the barnacles feeding.