What is this?

I found this egg-sack looking thing on my live rock the other day. It's about the size of a quarter. My LR has been curing for about 4 weeks now. Any ideas on what it might be?

 

Hmm, well they look like pineapple sponges to me. but i've never really seen them clump up like that so not for sure on it. google pineapple sponges and see if you can id it.

 

it kind of looks like it has purple tips

 

i may be wrong but check out Colonial tunicates ( Botrylloids sp ) .. color may be off but the structure looks about right..

Link...
Sponge Hitch Hikers

 

it kind of looks like my father in law's pink tip nem but that is way to small and bunched to be a nem

 

it looks like the start of an anemone but that would be a weird hitch hiker. new to me though. good luck finding what it is.

 

I was thinking they might be tunicates as well. But they seem awfully small, the individuals in the colony are only a 3 or 4 mm in diameter. Maybe they are babies.