The level 10 witch spell that brings the dead back to "life" as a zombie is iffy. It's good if you want a quick and easy resurrection with no ambrosia (yay) but bad if you want to use it as a zombie apocalypse tool. Though in my game, a bug with the bites makes a zombie apocalypse IMPOSSIBLES!
Because the resurrected Sim is now homeless, after they've muched the plant, the "permanent" zombie just leaves the lot to go "home" and is insantly cured. Not as a ghost but a regular Sim, making the only slightly feasilbe way for a zombie apocalypse (for me) is the potent zombification elixir and directly control the permanent zombie. Hope this gets fixed. Somehow.