Beta Tester, Weaver of Reality

Indestructible.
As long as your devotion to White and Blue is
less than seven, Beta-Tester isn't a creature
Once, during each player's turn, when any player
casts a spell, you may pay {w}{u}, if you do you
may change one game term on that card to another
game term. The changed game term stays in effect
until the card enters the graveyard or exile. (a game
term is any term that has a definition in Magic: The Gathering)