Brain Maze - Weird "root"-like extensions

[Eclyps19]

I have this guy in my frag tank going through QT, and every night it extends these long threads out of the same spot. They stick to the frag holder and spread like roots of a plant. I've never actually seen this before (this is my first brain maze), and I was wondering what exactly this extension is. It always retracts when the lights come on, but it looks nothing like the normal polyp extension of the main coral. Could somebody please enlighten me?

 

[UCF Alum]

It’s trying to sting that disc.
It’s a defense mechanism. Mine does the same thing when something gets too close. It will kill other corals so keep it away from others.

 

[Eclyps19]

Hmmmm... since it's doing it every single night, I wonder if it's getting stressed out. Maybe it'd be more comfortable in the sand bed. Should I consider moving it?

 

[UCF Alum]

Yeah. I’d probably move it over some. No need to worry though. Mine had been doing that off and on for years and is thriving. They are pretty resilient.