Impale vampires returning? (4)
I believe the answer is:
stab
'impale' is the definition.
(I've seen this before)
'vampires returning?' is the wordplay.
'vampires' becomes 'bats' (I've seen this in another clue).
'returning?' says the letters should be written in reverse.
'bats' reversed gives 'STAB'.
(Other definitions for stab that I've seen before include "Rough guess; to knife" , "Sudden sharp pain" , "Try - skewer" , "Injure with knife" , "Thrust at and pierce" .)