Crypts of Val'Habar

Whenever a creature dies, exile it and put a 1/1
Red and Green Skeleton Creature token on the
battlefield under your control.
{4}{g}{r}: Return a creature exiled with Crypts of
Val'Habar to the battlefield under your control.
It's a Zombie in addition to its other types.
Skeletons and Zombies you control have
desertwalk.