What is this

[bang guy]

Interesting Snail.
Does it have eye stalks? I can't see them in the pic. Is there a mouth at the end of the probiscus or is it just a siphon?
It sure looks like a Fighting Conch to me.
Is there any way you have an unwelcome hitchhiker?

 

[mrnemo]

I didnt see any eye stalks or mouth, and hitch hiker I am not sure about that unless it came with the Llyanassa Snails and they all looked allike

 

[bang guy]

Just some facts and we can eventually figure this out.
Fighting Conch (Strombus alatus) have a mouth at the end of their "trunk". They use it to scrape Diatoms or suck up detritus (yummy!).
They have two eye stalks and have pretty good vision. To the point where they can recognize individuals on the other side of the glass.
If yours doesn't have these characteristics then it's most likely a predatory Snail. One way to find out is to try feeding it a piece of table shrimp. If it's S. alatus the shrimp will be ignored, if it's predatory then the shrimp should be quickly devoured.
Regardless, the snail that laid those eggs is a predator. I don't know if it's the snail in the picture though.