With build up

[Danny19]

Hi All
I’m a noob to Saltwater and was hoping someone here can help me out with identifying what is in my glass.
The tank has a few Trochus snails and nassarius snails in it and i think it might be some sort of egg.

Thankyou in advance

 

[Sophie"s mom]

Definitely Cerith snail eggs.

 

[Danny19]

Are Cerith are a different snail again?
How would it be possible if i only get Trochus snails and nassarius snails.