Creature turned out not red (6)
I believe the answer is:
rodent
'creature' is the definition.
(rodent is a kind of creature)
'turned out not red' is the wordplay.
'turned out' indicates anagramming the letters.
'not'+'red'='notred'
'notred' with letters rearranged gives 'RODENT'.
(Other definitions for rodent that I've seen before include "Small gnawing mammal" , "Eg, mouse, squirrel" , "Toothy mammal" , "Creature such as a rat" , "Placental mammal having a single pair of incisor, 'gnawing', teeth" .)