According to my BF he was doing this all day. He started at about 12pm when we went down stairs, I took him out to go outside and his beard went back to normal, put him back in his terarrium and he was fine, I left to my parents around 2pm and when I came backhe was black bearded again, my BF said he was doing this for a good portion of the time I was gone. I think its because he is pissed off at his own reflection, ontop of being an adolecent dragon (he's between 10 and 11 months old). I'm going to cover up the two sides of his tank tomarrow and give him a nice warm bath and see what happens and we'll go from there.