In a spooky way (6)
I believe the answer is:
eerily
'in a spooky way' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for eerily that I've seen before include "In strange or unearthly way" , "In a spooky way" , "in a disturbing way" , "in a weird way" , "In a strange and frightening way" .)