ID on something i thought was algae but has strange behavior

[sparrowdetour]

I have reached out the reef-cleaners and he didnt know what it was. Asked around locally, no one knows. Notice the little white spots/nucleaus within the red spaces. I have never seen something like this. What ever it is is tough as hell. Thought it was a standard red algae but noticed the fish/urchinclean up crew didnt really seem to be impacting it.

*Has been RX dipped, no change.
*Appears a bit like a polyp or feather duster, very complex
*Slow growing
*Retracts when highly agitated. When you take it out of the water it doesnt change. But if a snail goes over it, it can retract into being unseen. Also retracted during a hydrogen peroxide dip.
*Has been been through a hydrogen peroxide dip.

[Moort82]

Can't make out how many tentacles each polyp has but if it's 8 then it's an octocoral but my money is on colonial hydroids.