Naafiri, the Darkin Dagger

Trample

Whenever Naafiri, the Darkin Dagger attacks, you may put a creature card from your hand onto the battlefield tapped and attacking. Return that creature to your hand at the beginning of the next end step.

When Naafiri, the Darkin Dagger dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.