Sheoldred, Whispering One - 108 M IMA

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
At the beginning of your upkeep, return target creature card from your graveyard to the battlefield.
At the beginning of each opponent's upkeep, that player sacrifices a creature of their choice.

mythic
Legendary Creature — Phyrexian Praetor
From the Magic: The Gathering set Iconic Masters.