Bookhouse Rig

Devoid (This card has no color.)
until end of turn, target library becomes
a 1/* colorless Praetor creature with a
counter of the type of your choice. The library's
toughness is equal to the number of
cards in the owner's library. (The creature
is placed onto the battlefield and is still a library,
if the creature would die this turn. The library is put
into the owner's graveyard, instead.)