Edge of Reality

While attacking, creatures your opponents
control get -1/-0 for each sealed card they own.
While attacking, creatures you control get +1/+0
for each sealed card you own.
At the beginning of each other player's end step,
that player may seal a card from their hand and
pay {1} for each sealed card they own. If they do,
they gain control of Edge of Reality and of all permanents they own.