Streetwise Spellknife

Infuse (As this permanent enters the battlefield, you
may exile a card from your hand face down. When it
leaves the battlefield, you may cast each card exiled
with it that costs less without paying its mana cost.)
Streetwise Spellknife can't be blocked.
Whenever Streetwise Spellknife deals combat
damage to a player, exile the top card of that
player's library and up to one target card from
their graveyard.