Bloodshed Riser

Bloodshed Riser costs {b} more for each
non-zombie and non-spirit creature on the battlefield.
As long as you control 4 or more zombies, on the beginning of each of your upkeeps and end steps, create a 2/2 black zombie creature token.
{1}{b}, {t}: Destroy target non-zombie or
non-spirit creature. Then, create a 2/2
black zombie.