Vermetid snail on back of other snails?

[proace360]

Snails from my LFS had these weird protrusions on their shell. I saw some white string coming from one on the lighter snail, but it didn't really look like the pictures I see online. Are these vermetid snails?

 

[KrisReef]

Common hitchhiker on larger snail shells. Remove the snail from the tank, scrape off the spiral snail shell to leave no protective space in the tube. Rinse with tap and drop the CUC snail back into the tank.

 

[Reefkeepers Archive]

Yes, vermited snails, do what above says though I'd definitely rinse with RO as tap contains things like chlorine and potentially heavy metals