Need help ID critter that has appeared

[#R_TST]

I have a hitchhiker or critter of some sort in my rock. I thought it was a hair algae but it will retract into the rock if I try to tweeze it out. And now I see it coming out more than one hole in my rock. Any idea what this is? Is is safe or do I need to figure out how to destroy it?

 

[metzer]

aiptasia

 

[blaxsun]

Aptasia. Kill it with fire.

 

[#R_TST]

Fire?

Aptasia. Kill it with fire.

 

[WheatToast]

Fire?

 

[WheatToast]

In all seriousness, Aiptasia, a hardy sea anemone, is one of the most (if not the most) notorious reef pests. They can rapidly multiply, overtake your rockwork, and sting livestock. Manual, biological (Aiptasia eaters), and chemical treatments exist to combat them.