Crush pie ruined by extremely destructive animal (9)
I believe the answer is:
millipede
'animal' is the definition.
(millipede is a kind of animal)
'crush pie ruined by extremely destructive' is the wordplay.
'crush' becomes 'mill' (mill is a kind of crush**).
'ruined' indicates anagramming the letters.
'by' is a charade indicator (letters next to each other).
'extremely' means to remove the middle letters.
'destructive' with its centre taken out is 'de'.
'pie' with letters rearranged gives 'ipe'.
'mill'+'ipe'+'de'='MILLIPEDE'
(Other definitions for millipede that I've seen before include "Bug" , "Many-legged creature" .)