Yra, Enlightened Seer

Accelerate {u}
When Yra resolves, draw a card.
When Yra dies, entomb it. For as long as it
remains entombed, you may cast it only for its accelerate cost. (To entomb a card, exile it. For as
long as that card remains entombed, you may cast it
by tapping an untapped creature you control in
addition to paying any other costs.)