Uncanny, creepy (5)
I believe the answer is:
eerie
This clue is a double definition.
'uncanny' is the first definition.
(I've seen this before)
'creepy' is the second definition.
(eerie can mean strange or creepy)
(Other definitions for eerie that I've seen before include "Spectral" , "Spine-tingling" , "Unnatural" , "Spooky, unearthly" , "Strange, unusual" .)