It’s cheaper to get the body than the head and that annoys my headless omega. And this should probably be in radicons
He actually does have a little tiny pop-up head. Aaron Archer specifically designed the toy with it do that, in case the Headmaster went missing, he's at least got something.
He asked why people is missing Omega's head and somehow, from the handful of answers, nobody actually told why they are missing their omega's head. My guess is, they had him from their childhood and lost them by playing with the thing instead of yous displaying him in a shelf.