Any idea what this is?

[Back where it all began]

This has been growing on my rock for the last three weeks or so. Evidently came with the rock and has been developing ever since.

 

[LesPoissons]

Looks like a type of brown macro algae to me, but not positive. Does it open more?

 

[Cherry Bomb]

Could be- http://www.flora.sa.gov.au/efsa/algae_revealed/pdf/Lobophora_variegata.pdf

 

[sfin52]

Could be- http://www.flora.sa.gov.au/efsa/algae_revealed/pdf/Lobophora_variegata.pdf

I agree

 

[reefwiser]

Padina fraseri

The Seaweed Site

www.seaweed.ie

 

[Back where it all began]

Thanks for all of your input. Now my Kole tang is eating it a piece at a time.