Algae/plant ID ?

[Tullimonstrum]

I just started my first reef tank and found this in the live rock, I bought the live rock from an established tank.
I have tried searching on google but I haven't found any match for this.

 

[Tahoe61]

Welcome to Reef2Reef

Possibly Razor Caulerpa, which can be very invasive. An image of the algae in your tank or submerged might assist in a definitive ID.

 

[cloak]

I think it might be either Caulerpa serrulata or Caulerpa scalpelliformis.

http://www.saltcorner.com/AquariumLibrary/browsespecies.php?CritterID=1992&filter=0

http://www.saltcorner.com/AquariumLibrary/browsespecies.php?CritterID=1991&filter=0

 

[Tullimonstrum]

Thanks for the welcome and thank you for narrowing it down. Here is a picture of it submerged(sorry about the bad quality).