I drew up a pattern, cut it out of an old t-shirt, sewed it up and added a string on the back ( for flying of course) and used embroidery floss for his mouth and googley eyes from a birthday card.
He also does this a lot with his "pet" bat and when he is dressed up like Batman. Makes a "bat shadow"
To say he loves it, is an understatement. When I went down to check on him before I went to bed, I found him with his bat in his hands.