So the whole concept of this is still something relatively new and I don't have all the details worked out yet but basically the whole idea behind this "New Moon" form is that he transforms to look like this in the dark and he glows in the dark. Now in a normal setting like in a dimly lit room he isn't necessarily affected aside from the fact that he kinda glows in the dark, but he does get behavioral changes when he changes into this form too. Every night he changes to look like this, and he gets more and more feral in behavior depending on what time it is, and this behavior change is linked to the phases of the moon, kinda like a werewolf but the inverse effect. Instead of being at it's strongest during a full moon, instead he's at his most feral during the New Moon when the night sky is at it's darkest and the power of the change is at it's strongest. I don't really have a story for why this happens or exactly how it happens but I thought it was a neat concept to play around with. I also thought it'd be fun to have him change when the room he's in is dark too because he glows in the dark and under a blacklight so I thought in like a rave or dance club situation it'd look rad as hell.