The guys at Cherry Corals have shared some amazing footage of a Vermetid snail, a common reef aquarium nuisance, feeding among Montipora corals. The snail casts a thin net of filaments downstream, capturing whatever it can ensnare, and reels it in. This feeding behavior, while interesting to watch, is harmful to nearby corals and invertebrates, as the filaments sting and will cause coral bleaching or tissue recession. The snails, which are actually encased in a stationary tube, usually hitch hike into the aquarium on live rock or already on coral frags and colonies. They can get quite large, very quickly, and will multiply rapidly if left unchecked.
To rid your aquarium of these pests, simply cut the tube worm out of the rockwork with a pair of bone cutters or apply some super glue or epoxy to the opening of the snail. You could also use the old Aiptasia remedies by injecting lemon juice or kalkwasser into the opening as well.