Unravel 
Instant
Counter target spell. If the amount of mana spent to cast that spell was less than its mana value, you draw a card.
Legality
standardLEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL
Instant
Counter target spell. If the amount of mana spent to cast that spell was less than its mana value, you draw a card.