Went off creature (4)
I believe the answer is:
newt
'creature' is the definition.
(newt is a kind of animal)
'went off' is the wordplay.
'off' is an anagram indicator.
'went' with letters rearranged gives 'NEWT'.
(Other definitions for newt that I've seen before include "Amphibian such as the salamander" , "Went to find kind of water lizard" , "found in pond!" , "Amphibian - a Ken Livingstone pet?" , "Small often colourful salamander of the Northern Hemisphere" .)