Instructions
The Sims 2: University
Have a Sim join the Paranormal career.
Reach level 5 of the Paranormal career to unlock the career reward Resurrecto-o-Nomintron.
Use the Resurrect-o-Nomintron to call the Grim Reaper. You will be presented with a phonebook of deceased Sims that your Sim knows. It will only show deceased Sims that have a gravestone or urn in the neighborhood. Select the Sim you want to create into a Zombie.
Pay the Grim Reaper between $988 and §4127 Simoleons to resurrect your Sim. The Sim will then be resurrected as a Zombie
The Sims 2: FreeTime
Create or improve a household so it includes several Sims with a high enthusiasm in a hobby and a Lifetime Aspiration. The more Sims you have that meet this criterion, the better your chances.
Wait for the Gypsy Matchmaker to deliver the lamp. There is a 2 percent chance she will appear each day for every Sim with a high Lifetime Aspiration.
Rub the lamp and summon the Genie.
Select "Resurrect" as one of your wishes. If the Genie wish fails, the Sim will be resurrected as a zombie.
The Sims 2: Apartment Life
Befriend a witch. Witches appear randomly on community lots and are more likely to appear on busy lots. You may need to re-visit a lot several times before a witch appears. Evil witches dress in black with black hats and have a green skin tone. They will also have a green aura similar to one a Sim has when their hygiene is low. Good witches dress in white and have a bluish glow.
Select "Teach me the path of the Dark" (or Light) once it appears in the interaction pie menu. You won't see it until your relationship when that Sim is high enough.
Increase your evil alignment so it is -90%. Alignment is decided by how the spells you cast. If you cast evil spells, you evil alignment increase. If you cast good spells, your evil alignment decreases.
Increase your magic skill until you reach level 9.
Collect two Dragon Scales, Eye of Newt and Viper Venom (six items total). Reagents can be created using the cauldron or purchased from the High Witch.
Cast the "Vivificus Zombiae" spell to create a zombie.
The Sims: Living Large
Wait for a Sim to die or kill off a Sim by locking them in a room and starving them to death. Do not use the pool to kill off a Sim because you won't be able to reach the Grim Reaper.
Wait for the Grim Reaper to arrive.
Plead with the Grim Reaper for the life of the Sim. The Grim Reaper will then engage you in a game of rock-paper-scissors. If you lose the game and the Grim Reaper is in a good mood. When a Sim loses the game, the Grim reaper may take the Sim or transform him into a zombie. Zombie Sims have green skin and lose all their personality points. Otherwise they are like normal Sims.