Skeletal Constructor

Obliterate Black (The creature with Obliterate exiles all black creatures it damages and cannot be the target of black spells or abilities.)
Delay {b}{b} (You may also pay this cards Delay cost. If you do, you can choose when it's ability resolves.)
When Skeletal Constructor is summoned, for each creature in your graveyard and all black creatures in enemies graveyards, summon a 2/1 black Skeleton creature token.