It could be you! (6)
I believe the answer is:
anyone
'it' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'be you' is the wordplay.
'be' becomes 'any' (I can't justify this - if you can you should believe this answer much more).
'you' becomes 'one' (I've seen this before).
'any'+'one'='ANYONE'
'could' acts as a link.
Can you help me to learn more?
(Other definitions for anyone that I've seen before include "Whoever" , "An unspecified person or persons" , "No particular person" , "Animal-hunting trip" , "Whosoever" .)