Happen to find ring with cold dog (5)
I believe the answer is:
occur
'happen' is the definition.
(I know that happen can be written as occur)
'ring with cold dog' is the wordplay.
'ring' becomes 'O' (letter resembling a ring).
'with' is a charade indicator (letters next to each other).
'cold' becomes 'C' (eg on taps).
'dog' becomes 'cur' (a cur is an aggressive or scruffy dog).
'o'+'c'+'cur'='OCCUR'
'to find' is the link.
(Other definitions for occur that I've seen before include "Happen, take place" , "Befall" , "Spring to mind" , "Turn up" , "Come to pass" .)