Ill-Timed Explosion 
Sorcery
Draw two cards. Then you may discard two cards. When you do, Ill-Timed Explosion deals X damage to each creature, where X is the greatest mana value among cards discarded this way.
Legality
standardLEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL