The Uncanny (Ger. Das Unheimliche - “the opposite of what is familiar”) is a Freudian concept of an instance where something can be familiar, yet foreign at the same time, resulting in a feeling of it being uncomfortably strange or uncomfortably familiar. (See Uncanny valley)
Because the uncanny is familiar, yet strange, it often creates cognitive dissonance within the experiencing subject due to the paradoxical nature of being attracted to, yet repulsed by an object at the same time.
This cognitive dissonance often leads to an outright rejection of the object, as one would rather reject than rationalize.