A creature that must cooperate in order to feed is the tug worm. Tug worms hide in burrows in the reef waiting for large false fish to pass close by. When one comes within range, they launch outward and insert their dual, sharp-tipped, jointed, silicon carbide tentacles through the flesh and wrap them around the bones of the animal. The tug worms have forward-facing hairs on their bodies that keep them firm in their tight burrows, which are lined with their own cement-like feces for a perfect fit, but an individual tug worm can still be ripped out (or apart) by strong prey. To capture large prey, three to twenty worms must have burrows near each other and work together.
Written by Daniel Noe, ChampionOfTheGalaxy.com