Ob Nixilis, the Adversary
Legendary Planeswalker — Nixilis
Casualty X. The copy isn't legendary and has starting loyalty X. (As you cast this spell, you may sacrifice a creature with power X. When you do, copy this spell. The copy becomes a token.)
+1 : Each opponent loses 2 life unless they discard a card. If you control a Demon or Devil, you gain 2 life.
−2 : Create a 1/1 red Devil creature token with "When this token dies, it deals 1 damage to any target."
−7 : Target player draws seven cards and loses 7 life.
If you pay the casualty cost of a spell, the copy will resolve before the original spell.