Aa'-Alí, Undead Caretaker

All creature cards in all zones are zombies in
addition to their other types.
During each player's upkeep, that player
sacrifices a zombie, then you put a zombie from
that player's graveyard onto the battlefield under
your control.
{b},pay 1 life: create a 1/1 black zombie.
{g}{g}{g}:put a +1/+1 counter on each zombie you control.
{2}{u}: return Aa'-Ali to it's owner's hand.