Tuulen, the Stellestrial

Whenever you cast an instant or sorcery spell,
exile that card instead of putting it into your
graveyard as it resolves. Return that card to your
graveyard at the beginning of the next end step.
At the beginning of your postcombat main
phase, if you gained 8 or more life this turn,
you may cast a copy of each card exiled by
Tuulen without paying their mana costs.