Sion, The Undead Juggernaut

Haste, Double strike
If Sion would be put into the Graveyard from the
battlefield, any counters he has aren't removed.
whenever a player discards a card or sion destroys
a creature sion gains +1/+0.
{x}{b/r}{b/r}, return Sion to the battlefield from the graveyard to the battlefield and give him {x} -1/-0 ({x} equals the number of times Sion has entered
the graveyard this game)