I guess I have a wall. The guy I bought it from called it an octopus frogspawn. It's a monster. I have it on a rock about the size of a closed fist and when it closes it is tiny. When it open though, it's the size of a volleyball. I've never seen another one besides mine so I can't compare it to tohers, but mine its dark green with light green tips. Not as pretty as otehrs, but an interesting piece. I haven't found it to be sensitive to anything. I keep it on the bottom in medium flow under t5 HO 4x54w in a 60g tank. I feed minimally and only have a couple of fish in the tank that take prepared foods, so it doesn't get much but never seems to any worse for not eating. I have no heater on the tank, it's kept warm by the lights in the day and what ever heat the pump gives it. I keep my house in the mid 70's. I constantly battle with low alk even though I do partials every week.
So, even with my poor reefing, mine is flourishing. I went to move it yesterday becasue even though I keep it 3-4" away from everything, it has made a 'mat' that is moving towards my rocks. I have also found it to be nasty. I never noticed any sweepers until I put some zoas near it. BAM! Out they came and wacked my zoas.