Occasionally asked after low creature (5)
I believe the answer is:
moose
'creature' is the definition.
'occasionally asked after low' is the wordplay.
'occasionally' means one should take alternating letters.
'after' is a charade indicator (letters next to each other).
'low' becomes 'moo' (both can mean to make the noise of a cow).
The alternate letters of 'asked' are 'se'.
'se' after 'moo' is 'MOOSE'.
(Other definitions for moose that I've seen before include "North American deer" , "Animal" , "Large N American deer like European elk" , "North American elk" , "Large US deer" .)