No clue as to what this is

[FenReef]

I've got about a half dozen of these things, they seem harmless.
looks like a small grit covered gumdrop.

it's not a sponge (I think)
it's not slimy, kind of gritty
it's not squishy, kind of firm.
doesn't move
not slimy
no openings that I can see

I posted this question on another web site but no one had an answer

 

[tazdevil]

If it's white in color, I'd bet it was an eggsack.

 

[FenReef]

thanks for the reply.
from what i can see it looks dark under the grit.
i doubt it's an eggsack they've been there for 3-4 months. might have been there from the beginning