Macro ID help please

[Salt1823]

This came in as a tiny piece on a piece of live rock. It grows insanely fast. I can't get rid of it with manual removal. Any ideas what it is or what might eat it? Lawnmower blenny didn't touch it. Emerald, blue leg hermits, red leg hermits and scarlet reef crabs haven't touched it.

 

[Lovemyreef2015]

Looks like either Caulerpa brachypus or Caulerpa prolifera.

 

[Salt1823]

Looks like either Caulerpa brachypus or Caulerpa prolifera.

Thank you for the Id! Any suggestions for what might eat it?

 

[Lovemyreef2015]

Thank you for the Id! Any suggestions for what might eat it?

You're welcome. I believe tuxedo urchins will eat it.

 

[Salt1823]

You're welcome. I believe tuxedo urchins will eat it.

It's brachypus I looked it up after your direction. Thank you again.