Similar in feeling:
* Uncanny: This emphasizes the strange and unsettling nature of something that is beyond normal comprehension.
* Spectral: This suggests a connection to ghosts or spirits, emphasizing a feeling of ghostly presence.
* Spooky: This is a more casual word for something that makes you feel scared or uneasy.
* Creepy: This emphasizes a feeling of revulsion or disgust, often associated with something sinister.
* Uneasy: This focuses on the feeling of discomfort and anxiety that something eerie might cause.
* Weird: This is a general word for something that is strange or unusual.
More specific:
* Sinister: This suggests something evil or threatening.
* Ominous: This suggests something bad is about to happen.
* Disquieting: This emphasizes the feeling of being unsettled or disturbed.
* Unnerving: This suggests something that makes you feel nervous or anxious.
The best synonym to use will depend on the specific context of your writing.