Battlefield Scavenger 
Creature — Jackal Rogue
You may exert this creature as it attacks. (It won't untap during your next untap step.) Whenever you exert a creature, you may discard a card. If you do, draw a card.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL