What are these? Possible algae?

[terrell wohlrab]

These just seemed to pop up over night. The protrude from the rock and kinda look like a worm. Is this a form of coraline?

 

[ewelch]

Vermetid Snail

 

[Palyzoa]

+1 for Vermetid snails. Can become a nuisance if they continue to multiply, their mucus web catches near by food in the water but can irritate corals sometimes. You can manually remove them with tweezers or super glue the opening of the tube shut to to control the population.