Realistic robots feels creepy

Research explored some of the reasons people view robots that are too realistic as creepy.

• Human replicas cause creepy perceptions, known as the "uncanny valley." They found that exposure over time decreases the perception of uncanniness.
• While robots can have some human features, there can be too much of a good thing. That can produce feelings of unease, eeriness, and revulsion.

Perhaps that is why animated dolls are more associated with characters in nightmares, regardless of usefulness.