The beautiful fan worm
Sabellastarte australiensis is both gorgeous to watch as well as fun to play with.
That peacock-like fan is actually the feeding tentacles of a non descript looking worm that lives in a mud tube. If you have not already spooked it you get the chance to photograph it. If the camera strobes have not spooked it you get the chance to touch it. When you do touch it, ... in the briefest blink of an eye it all disappears back into the mud tube where the rest of the worm remains safe from predators.
If you are patient enough to wait for the fan to re-emerge you get to do it all again.
Photo: Robert Rath, ‘Day 654, No Ordinary Worm', 1/50s f/11 ISO320 100mm