Mine does the same thing like everynight. He will climb up and get himself wedged between the little thing that sticks out on the tank(was to hold the lid on the fish tank) and the screen top. The first time he did that it scared me looked over at his tank at like 1 in the morning from my bed and couldnt see him in the tank so i figured he was behind something then i see this small bp fall from the top of the tank then he gets up and does it again. Hes going to hurt himself cause he keeps on doing. I got pics of him doing it to. Oh and after he falls and just looks at me like why wont it open.