Kunyu, Master Improviser

Spontaneous—{3}{u}{r} (You may reveal this card when you draw it and cast it for its Spontaneous cost.)
When Kunyu enters the battlefield if its Spontaneous cost was payed, scry 5.
Whenever you cast a spell for its Spontaneous cost, you may put Kunyu on top of its owner's library.
{x}{u}{r}, {t}: Scry X.