Sidisi, Regent of the Mire 
Legendary Creature — Zombie Snake Warlock
, Sacrifice a creature you control with mana value X other than Sidisi: Return target creature card with mana value X plus 1 from your graveyard to the battlefield. Activate only as a sorcery.
Legality
standardLEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL