I made this guy about 3-4 years ago. The mask began as a wire skeleton frame, I used papier-mâché to build up the dome of his head and his jaw. I utilized foam, thick yarn, burlap fabric and a LOT of hot glue to build on the details of his neck. I casted simple teeth shapes in some clay and used cheap resin from a craft store to make them. I shaped each tooth by hand with a dremel and made the gum tissue out of hot glue. He is painted with acrylic paint, and sprayed over a million times with clear gloss spray. For theatrical purposes, I will utilize a cheap voice changer, some glycerin, and the use of my vape mod to make some smoke.
Considering I have no professional equipment or education with this, I'd say he turned out alright. I made a whole costume but it was rushed and did not come out as well as the mask. I've since tossed out the body portion and I kept the gloves/mask for a quick costume if I need one.
The costume was a spandex black morphsuit with pool noodle foam and lots of hot glue (which I had to apply while it was on other wise it would shrink). The feet were high heels with the heels cut off and claw toes attached. The tail was a large pool noodle that was carved into the shape with paper/tape/hot glue spines going along it. I must have spent around $120 on hot glue alone
Here is a theatrical video with the mask on, please don't mind the birds in the background