Velja, Ojutai Tempest

Flying, haste
When Velja, Ojutai Tempest enters the battlefield, you may search your library for an instant or sorcery and put it into your hand. Then shuffle your library.
Whenever you cast an instant or sorcery, Velja, Ojutai Tempest gets +X/+0 until end of turn, where X is that spell's converted mana cost.