critter that fills holes in LR?

[canuckzilla]

I have this one porous LR that is slowly having every opening stuffed with rubble from my LS. Anyone know what this home builder could be?

The only thing I've seen in the area is a medium size brittle star.

thanks!
Gary

[AJ_77]

Crab!

[takphan]

my mantis shrimp often does that

[G1GY]

I had some of them little hairy crabs doing that. (Untill they got evicted.) :biggrin: