Help Identifying this thing coming out of my favia's tissue

[JohnRiv]

I have a 20 g reef it's been running for 3 months now, I got this dragon soul favia a month ago and it's been doing great, a little over 2 weeks ago this little thing started to appear out of the favia, it's been getting a little bigger but no ill effects so far, I was wondering if someone knew what it is and if it's bad for the coral.

 

[C. Eymann]

Pics are pretty fuzzy, barnacle ? maybe gall crab?

 

[C. Eymann]

Also I believe you have a goniastrea there, commonly mistaken as favia, goniastrea palauensis maybe?

 

[JohnRiv]

Also I believe you have a goniastrea there, commonly mistaken as favia, goniastrea palauensis maybe?

Here's a full picture of it, I also notice that that little things retracts back inside during the night, I'm concerned it my harm the coral down the line

 

[DSC reef]

Agree with goniastrea. Possibly mesenterial filaments