What is the string branch growing off coral?

[SvenLink]

Hello, new to coral (sort of). These corals are getting a new home today and I am doing a dip. However I finally got around to asking what these branch looking things are on my coral. Ones starting to grow on a snail too. Is it anything I should be worried about?

 

thanks

[yoshii]

Vermetids, "harmless" but annoying. They extend a muscus string to feed which looks ugly and can sometimes irritate coral. Also the tube can cut your hand if you grab them. I would scrape them off, just make sure to get the whole thing off, not just the part of the tube that sticks out.

[SvenLink]

Awesome thank you!  Is it something that can be prevented in the future or just part of the life of the aquarium?

[Tired]

They come in on live rock and coral. If you physically remove the whole thing, they don't come back, but it's very easy to accidentally introduce a few. 

[SvenLink]

Awesome! Thank you. My questions are resolved.