Any idea?

[Zaccolwlell]

Just found this on my new live rock in my new tank. Anyone have a clue what this is?

 

[Betta132]

Appears to be a sponge of some variety. It may spread a bit, but it's perfectly harmless and won't overtake anything. Just leave them alone.

 

[Calappidae]

Looks like colonel hydroids to me.

 

[rssjsb]

I'm thinking some type of filter-feeding cucumber.

 

[Zaccolwlell]

It's just coming out of the rock, kinda white and veiny where it's from

 

[Nina51]

can you get a clearer picture? this would be pretty far fetched but not unheard of, google basket starfish.

 

[Betta132]

Poke it with something and see what it does. Don't touch it, it might sting.