In The Sims, if a Sim dies, a loved one can plead to the Grim Reaper and engage in a rock-paper-scissors game for the life of the Sim. If the Sim loses, but the Grim Reaper is in a good mood, he'll bring back the deceased Sim as a zombie. Zombie Sims retain all of their skill points, but lose all of their personality points, as well as gain a green tint to their skin. Besides this, zombies act like normal Sims and can die (again... ) like living Sims.
The Sims 2
Zombies are only available through The Sims 2: University, The Sims 2: FreeTime and The Sims 2: Apartment Life. In University, Zombies are made through use of the Paranormal career reward. Sims who died can be brought back through the use of the Resurrect-O-Nomitron. If a Sim bids between §998 and §4127 when using the Resurrect-O-Nomitron, a dead Sim will come back to life as a zombie. In Freetime, if a Genie resurrect wish fails, the Sim will return as a zombie. In Apartment Life, one of the evil witch spells is to bring a dead Sim back as a zombie.
He or she returns with a blueish skintone, distorted facial features, and a set zombie Personality. (While zombies have a set personality, a zombie's personality can be edited with SimPE or by using the boolprop testingcheatsenabled true cheat. If Apartment Life is installed, zombies are affected by Magically Spiced Sugar and Enchanted Essence of Cur Tails.
Zombies cannot walk, skip, or run - they move with a zombie "shamble". Skill points are also lost. The new zombie Sim will have a lowered daily and lifetime relationship score towards the Sim who brought them back as a zombie. Zombies are only able to age if they are Teens. They can get scholarships and go away to College, when they return they will stop aging therefore, they do not die of old age. Occasionally a Sim may react in a disgusted way when a zombie enters a room. Creepily, zombie Sims will occasionally think of brains. While it is possible for Sims to enter relationships with zombies both male and female zombies are sterile. That being said, if a pregnant female or alien-pregnant male is resurrected as a zombie, they will carry that child to term, though the child will be normal, possessing none of the Zombie qualities. Zombies always have low hygiene levels.
Beware when deciding to make a Zombie, as once the Sim has become undead, they cannot be cured without the use of a hack such as the InSimenator or a program such as SimPE, meaning that your most beautiful Sim will now be doomed to an undead existence!
Unlike in horror films, Zombies cannot usually eat brains or turn other Sims into Zombies, but Mods do exist which add such interactions.