Abandoned Negotiations

Creatures can't attack you or planeswalkers you
control unless their controller pays {3} and 3 life
for each of those creatures.
If a creature you control attacks, sacrifice
Abandoned Negotiations.
"Our accord is done for, our war won. They squabble
as they please, and we do not care until they interfere
with us. Time is nothing to a perfect machine."
-Mother Matricies