Lukaas, the Forever

If four or more creatures were destroyed this turn you may cast Lukaas, the Forever without paying it's mana cost.
Sire {1}{b}{r} -- Exile the top card of your library.
If it's a creature card create a token that's a copy
of the exiled card. It's a vampire in addition to its other types.
Sacrifice a creature: Regenerate Lukaas, the Forever.