What the heck??!?

I have this one on DVD and I'm stumped over this one scene at the plastic surgeon's - this bald-headed doctor with a ring of black hair and a mustache does his work, then as he pulls back his 'stache is gone...then a few seconds later the rest of his hair is gone too, just before he ends up with Droopy's head! I mean, this is one crazy cartoon, but that's one level of crazy too far!