Anivia, the kryophoenix

Whenever you cast an instant or sorcery tap target creature and put a stuncounter on it.

{2}{p/r}: Sacrifice Anivia, the kryophoenix to
draw two cards.

When Anivia, the kryophoenix is in your graveyard you can cast it without paying its manacost whenever you tap a creature an opponent controls.