Anybody???

[marie]

looks like a type of sponge to me, sponges like everything else in the tank will fight for room to grow. It is possible it could be irritating the palys but it probably won't grow as fast.

I personally wouldn't worry about it, the palys will probably just grow in different directions instead but if you do decide to hack it off it might be a good idea to rinse the rock well before putting back in tank