Life state

Each expansion pack for The Sims 2 released to date has added an alternate state in which sims can exist. These states have unique triggering techniques, advantages and disadvantages. These states are:
 * Humans (or Sims)
 * Ghosts (The Sims 2)
 * Aliens (The Sims 2)
 * Zombies (University, FreeTime, Apartment Life)
 * Vampires (Nightlife)
 * Servos (Open for Business)
 * Werewolves (Pets)
 * PlantSims (Seasons)
 * Bigfoot (Bon Voyage)
 * Genie (FreeTime)
 * Witches (Apartment Life)

Each life state offers new opportunities for the sim, making certain aspects of play easier to handle and others harder.