ok not a species ID.
I would call it sick
degenerative tissue = abundant
exposed skeleton some sort of "brain" <can you think of any thing more obscure? sorry lower flow, medium light, feed tentacles if you see them. (these are guesses based on your picture.) dont let it sit in a low/no flow area it can lead to detritus realted hydrogen sulfide release (further killing sick flesh) low but not no flow...... erghh explaining it is so difficult.