Undercity Arborus

As long as Undercity Arborus is on the battlefield or in your graveyard, whenever you gravecycle a card you may pay {b}. When you do, create a 2/2 black zombie creature token.
Gravecycling {2}{b/g}{b/g} ({2}{b/g}{b/g}, exile this card from your graveyard: draw a card.)