I have a tuxedo urchin in my tank. He's always picking things up and carrying them around. He actually fragged my zoanthids that way once. While he does clean algae off the back wall, he much prefers to strip a rock of all it's coralline algae. While he is very interesting to watch and look at, he can be kind of a pain at times, moving things that I don't want moved, and turning some rocks white with his feeding.
Someone stop me! Please! But... not just yet...
55 Gal Tropical FW
55 Gal Mixed Reef