It's an ape costume that's been dyed white, and there's a plastic horn glued to the head. It's difficult to imagine that anyone didn't have a hard time believing this monster: it was little more than a rental costume. A costume suit is the easiest and less believable type of effect, but they really didn't try with this one. Remember the Gorn outfit? At least with that one they created skin texture, eye detail and some facial movement, but this was a fake fur gorilla suit that could have been picked up in the local rental store and gluing a horn on top of it. Very low points for effort. And with respect to the horn, just like the poor cocker spaniel that had one attached to its head to create the Alfa 177 canine, it seemed that the horn was the default characteristic for defining alien-ness. Without any question, the Mugato was probably one of the alien races with the highest suck factors. But then, at least you couldn't see the zipper.