Whenever a non-black creature is put into any graveyard from play, put a husk counter on Necropolis of Azar.
, Remove a husk counter from Necropolis of Azar: Put a Spawn of Azar token into play. Treat this token as a black creature with a random power and toughness, each no less than 1 and no greater than 3, that has swampwalk.