Mad turns creating shock (4)
I believe the answer is:
stun
'shock' is the definition.
(both can mean to surprise)
'mad turns' is the wordplay.
'mad' becomes 'nuts' (I've seen this before).
'turns' shows that the letters should be reversed in order.
'nuts' backwards is 'STUN'.
'creating' acts as a link.
(Other definitions for stun that I've seen before include "Astound; render senseless" , "Shock, flabbergast" , "cause amazement" , "Daze, knock senseless" , "Daze, overwhelm" .)