Answer: eeriest

AnswerCrossword Clue
EERIESTSuperlatively Halloweenlike
EERIESTMost ghostly.
EERIESTMost weird.
EERIESTVery spooky.
EERIESTStrangest
EERIESTHave the ... feeling
EERIESTMost scary
EERIESTMost spine-chilling
EERIESTMost Halloweenlike
EERIESTMost like a ghost
EERIESTMost inexplicable
EERIESTSuperlatively strange
EERIESTSupremely spooky
EERIESTStrangest.
EERIESTLike H. P. Lovecraft among all popular writers?
EERIESTMost chill-inducing
EERIESTOtherworldly in the extreme
EERIESTSuperlatively Kafkaesque
EERIESTMost unnerving
EERIESTMost chilling
EERIESTMost mysterious
EERIESTCausing the most goose bumps
EERIESTMost Halloween-like
eeriesteerie
eerieststrange and mysterious; unsettling
eeriestEERY, weird (strange (unusual (not usual)))
EERIESTLike the best occult films
EERIESTMost unworldly
EERIESTMost macabre
EERIESTSuperlatively weird
EERIESTMost unearthly
EERIESTSpooky to the max
EERIESTSuperlatively spooky
EERIESTFreaky to the max
EERIESTMost likely to cause horripilation
EERIESTMost likely to cause goose flesh
EERIESTHalloween superlative
EERIESTMost uncanny
EERIESTMost creepy
EERIESTMost Twilight Zone-like