Predecessor can store bananas (8)
I believe the answer is:
ancestor
'predecessor' is the definition.
(I've seen this before)
'can store bananas' is the wordplay.
'bananas' indicates anagramming the letters (informal term for mad).
'can'+'store'='canstore'
'canstore' with letters rearranged gives 'ANCESTOR'.
(Other definitions for ancestor that I've seen before include "Predecessor" , "one is up a tree" , "One of one's forebears" , "Antecedent, forebear" , "descent comes from one" .)