Nassarius Snail Question?

[mony97]

What does it mean when these little guys decide to chill on my LR vs burying themselves in the sand for long periods of time?
About 1/5 of my small regular nassarius snails have up and decided that this may be fun, and I have no idea why.. Any thoughts or knowledge?
Thx

 

[al&burke]

Mine come out during feeding times, I have only noticed them once on the LR. How knows what they do at night. They should be fine they could be laying eggs or something.