Blatant Knavery

Prowl {2}{u}{b} (You may cast this spell for its prowl
cost if you dealt combat damage to a player this turn
with a Rogue.)
When Blatant Knavery enters the battlefield,
discard two cards unless its prowl cost was paid.
Whenever you cast a Rogue spell, if its prowl
cost was paid, you may draw a card. If you do,
target player mills a card.