ID please in the blue circle

[mah0031]

 

[S-t-r-e-t-c-h]

Looks like aiptasia...

 

[garethwood]

plus 1 on the aip /\

 

[Big G]

Little hard to see in the dark crevice, but looks like aiptasia.

 

[Crabs McJones]

Agreed, looks like a single aptasia. Are you able to remove the rock that it's on? Best bet, if you just have the one, is remove the rock, scrape it off, and put epoxy or superglue over the spot it was on to make sure it doesn't grow back

 

[Dsnakes]

Looks like aiptasia...

Yep, the demon itself crawling up from it's dark crevice.