Our lot turned up to develop a monster (8)
I believe the answer is:
werewolf
'a monster' is the definition.
(I know that werewolf is a type of mythical creature)
'our lot turned up to develop' is the wordplay.
'our lot' becomes 'we' (we ourselves).
'turned up' shows that the letters should be reversed in order.
'to develop' becomes 'flower' (flowering is a kind of developing).
'flower' backwards is 'rewolf'.
'we'+'rewolf'='WEREWOLF'
(Other definitions for werewolf that I've seen before include "Hairy beast" , "one bewitched" , "lupine menace" , "Full moon howler" , "one who can become beastly" .)