What is this???? Need ID ASAP

[Mavilez]

I was looking as a Blasto I have and I found this on the side. Can someone tell me what it is? If it is a pest I want to get on top of it ASAP.

 

[MechEng99]

Looks like a vermetid snail or some close relative. They're filter feeding worms that send out a mucus strand to collect food. If your water has high nutrients, they'll reproduce to plague proportions. If not, then they'll stay manageable. They're not *bad*, but they can irritate coral with their mucus, can be unsightly, and they HURT if you jab your finger on one.