yielding of the Thirteen

( you may cast a legendary sorcery only if you control
a legendary creature or planeswalker. )
As an additional cost to cast Yielding of the
Thirteen, sacrifice thirteen nontoken creatures.
Destroy all creatures and planeswalkers you don't control. Then each opponent loses 7 life, discards
his or her hand, and exiles his or her graveyard.
We are the Thirteen, from now until the darkness
claims us.