Large creature Pat and Helen shot (8)
I believe the answer is:
elephant
'large creature' is the definition.
(large animal)
'pat and helen shot' is the wordplay.
'and' is a charade indicator (letters next to each other).
'shot' is an anagram indicator.
'pat'+'helen'='pathelen'
'pathelen' with letters rearranged gives 'ELEPHANT'.
(Other definitions for elephant that I've seen before include "Animal with a trunk" , "Endangered Species" , "Then leap (anag.)" , "Trunked mammal" , "Trumpeter" .)