Polymorph Persistence

Spells that change a creature's form do not
remove that creature from play. Instead, they
cause the card to be flipped face down and the
Token is used to cover it instead.
If the token would be exiled, remove the token
cover and exile the face down card instead.
At the beginning of the game, both players must
agree if Counters on and things attached to such
a creature remain unchanged or not.