Bottom Feeder

Stalk costs you pay cost {1} less to pay.
When Bottom Feeder enters the battlefield, if its
stalk cost was paid, choose a card you own in a graveyard or in exile and put it into your hand.
Stalk {u}{b} (At the end of each block step, if there
is an unblocked creature attacking you, you may cast
this card for its stalk cost. If you do, choose an
unblocked creature attacking you. This creature blocks
that creature.)