Ember, Keeper of the Abandoned

Lifelink

Extort (Whenever you cast a spell, you may pay {w/b}. If you do, each opponent loses 1 life and you gain
that much life.)

At the beginning of your postcombat main phase,
if you gained 3 or more life this turn, exile Ember,
Keeper of the Abandoned, then return her to the battlefield transformed under her owner’s control.