Similar meaning, but less intense:
* Uncanny
* Strange
* Uneasy
* Weird
* Mysterious
* Unsettling
* Spooky
* Otherworldly
* Bizarre
* Sinister
More intense and negative:
* Creepy
* Ghastly
* Macabre
* Haunting
* Spectral
* Ghostly
* Chilling
* Menacing
* Ominous
More specific to a particular feeling or situation:
* Melancholy (evokes sadness)
* Foreboding (suggests impending danger)
* Disturbing (indicates discomfort or unease)
* Disquieting (similar to disturbing, but with a sense of unease about the unknown)
The best word to use will depend on the specific context and the desired effect.