Manikins used for dental training are either deep into uncanny valley (creepy) territory if they try and look at all realistic, or just plain terrifying in their more abstract incarnations. A lot of this is just becuase (a) people are very good at interpreting faces and anything face-like seems possessed, (b) dental manikins have to bare their teeth so often have bizarre expressions. Anyhow, they are quite interesting, particularly the vintage metal ones which are a nastily grotty and beaten up.