Turd looking worms?

Sorry for the topic, but it's honestly the only way I can think of to call this. Here are some pics. I've tried doing some searches and so far haven't been able to come up with a positive ID. They're popping up everywhere














Sorry for the excessive amount of pictures. I took a 'picture inventory' of my tank while taking the pics for the ID and tried to photograph as many as I could so I could get a good idea of the population.

At any rate, any help identifying and/or advising if they are good or bad would be great. Also, when you get near it, it will suck in leaving the empty hard tube.

 

Vermetid snails I do believe.

 

vermetid snail.

 

I try to scrape as many off the rocks I can find.If it comes back if I don't get it all super glue the end closed.

 

Thanks! As far as I can tell the only real problem they present is they can overpopulate clogging things etc. I'll try and remove them by hand but unfortunately may have bigger problems at the moment