Citlali, Obsidian Opalstar

Flying, Vigilance

Whenever Citlali, Obsidian Opalstar deals combat damage to a player, exile the top card of that player's library. You may cast that card without paying its mana cost.
Whenever you cast an instant or sorcery spell, you
may exile a card from your hand. If you do, create a 1/1 white Spirit creature token with flying and you gain life equal to the exiled card's mana value.