Heeeeelllllpp!

[I.r.alien]

Trochus snail has this hard thing on its shell. There is something hard growing on its shell and I noticed when it was grazing.... SOMETHING CAME OUT OF IT TO EAT THE ALGEA! What could it be?!

Bonus thanks if you ID the other white thing!

 

[I.r.alien]

 

[reefermadnes5]

What is it? Not my area but im super curious.

 

[The_Paradox]

Looks like a barnacle to me.