tube worm pest

Can anyone help ID whether this is a vermetid snail or some other sort of tube worm? It looks like it's growing out from the skeleton of my acan.

So I've started seeing these random white tubes along my sandbed and rockwork. Any ideas on what they might be? A worm? I'm really not sure.

I'm thinking tube worm not sure they're all over all my rocks however.

Hi all, I have a two year old reef aquarium. Tube worms are becoming a pest for me, I literally have hundreds, and some og them in zoa colonies. Do any of you know why they spread to mush, and how I can prevent this? Peter