Hawwah, Oscillator of Souls

Flying, indestructible, lifelink
Whenever Hawwah deals combat damage to an opponent, you may instead pay that much life. If
you do, cast an artifact or instant spell you own
from your hand or in exile. It costs {x} less to cast,
gets +X/+X, where X is that much life, and is a creature in addition to its other types.
Infinite power harnessed within a soul of quartz.