In a creepy way (6)
I believe the answer is:
eerily
'in a creepy way' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eerily that I've seen before include "in a weird way" , "how to seem frightening" , "In spooky or ghostly manner" , "In strange or unearthly way" , "In a spooky way" .)