White organism??

[HJWJR]

What is this white thing on my rock.

 

[carri10]

I assume it doesn’t move, in which case I vote for a sponge.

 

[Science/G]

Probably some sort of tunicate

 

[Crabs McJones]

Sponge gets my vote

 

[HJWJR]

Thanks for the replies. Showed photo to Angie owner of local aquarium supplies in town .She also believes that it's a sponge. Thank you again.