Worm ID

[JohnL]

These are on some "real reef rock" sold at an lfs as live rock. Some kind of worm?

 

[reefing102]

Hard to tell but maybe a Medusa worm tentacle

 

[JohnL]

These come out from inside the rocks

 

[reefing102]

Mine came in on my KP rock

 

[kharmaguru]

These are on some "real reef rock" sold at an lfs as live rock. Some kind of worm?

Video looks like Digitate Hydroid. The pictures are hard to tell. Can annoy corals and make them stay closed. Can become a plague or disappear.