Mutually Assured Protection

As you cast Mutually Assured Protection, choose
an opponent. You and the chosen opponent have
protection from each other until your next untap
step. Neither player may attack the other, or cast
spells or activate abilities that target the other or
a permanent the other controls.
Then place Mutually Assured Protection at the
bottom of your library.
The bond formed in these contrived alliances
does not last, but while it does, it is unbreakable