What are these "roots" on my this stylophora?

[undbulsu]

Noticed them this morning. Just wondering what they are called and what their purpose for the colony is. Or are they some sort of parasite? The first image is of the coral colony and the second shows the roots up close. They are located on the underside of the colony

 

[Halo_003]

Looks like possibly vermetid snails? I think they qualify as a minor pest but I hate them.

 

[Mmoore0324]

Based on the photo I would say vermetid snails. Do they appear to be hard calcareous tubes? If so, then most likely vermetids. Bumble Bee snails will go after them 50/50. Personally, I just put a dab of super glue on their opening and that seems to do the trick. They will irritate corals.

 

[undbulsu]

Thanks. Never noticed them before. Had some bumblebee snails in the past, but no longer. Maybe that's why I am just seeing them now.