If you have one of those Talking Douglas Fir trees here is a cool talking skull idea.
“I took him out to the garage and disconnected his eye and mouth motors from the main post. I then used 2 – 2″ screws and attached the jaw to the motor of the douglas talking fir(DTS now) I used hot glue and sealed the screws to the mouth to insure no slippage. I made a fitting in the skull with a 90 degree fitting and a 3″ piece of PVC that I attached to the inside of the skull with screws. I can now attached the skull to the crossbones, or remove it, since the fitting on the crossbones is a male, and the one on the skull is female, making storage, setup, and fixing easier!”