Dark strange thing (5)
I believe the answer is:
night
'dark' is the definition.
(night is a kind of dark)
'strange thing' is the wordplay.
'strange' is an anagram indicator.
'thing' is an anagram of 'NIGHT'.
(Other definitions for night that I've seen before include "Opposite of day" , "See 8" , "Saturday -- Fever (film)" , "See 1 Across" , "For most, the time for sleep" .)