What is this?

[Katorin]

Hi

Not sure what this is but it's growing on a piece of live rock.
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Anyone know what the orange/red stuff is?

[Snaz]

Red bubble algae and a real nuisance. If you can remove that rock without breaking the delicate red bubbles do so ASAP. Once it is in a tank I think it is impossible to get rid of... I gave up.