Undead Army

At the beginning of your upkeep, create a 2/2 black Zombie creature token.
Sacrifice a creature: Put a +1/+1 counter on each Zombie you control.
If a Zombie you control dies, create a 1/1 black Skeleton creature token.
As long as you control ten or more Zombies, they have menace (can’t be blocked except by two or more creatures).