Januth, Supreme Necromancer

Your graveyard has hexproof. (Your graveyard
can't be the target of spells and abilities your opponents control)
At the beginning of your upkeep, you may pay {x}{p/b}. If you do, return target creature with converted mana cost X or less from your graveyard to the battlefield, except it is a black Skeleton in addition to its other colors and types.