Joyok, Crypt Menace

Whenever a creature you control dies, shuffle it back into your library and create a 2/2 black zombie creature token.
At the beginning of each of your upkeeps, look at the top card of your library. If it's a creature card, you may reveal it and put a 2/2 black zombie creature token into play.
"I'll make my servants rise quicker than you can think. Best you just end yourself now".