White Stalky Branches, what are they?

[mnavick]

These are slowly growing out from inbetween my rocks (just in this one spot), not fast but are growing. Any thoughts on what they are?

 

[MARINECRITTERS]

While I can not give you a direct ID it is harmless.
looks like a sponge or a species of codium algae.

 

[PistolShrmp]

I would venture to say it's a sponge.