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:

Aliens: Released with the base game. If an adult male sim is abducted while stargazing with the expensive telescope, he returns pregnant with an alien baby. Most of the time, this baby is born with green skin and possibly with solid black eyes. When transitioning to toddler may express facial features not usually found on normal sims. These attributes can then be passed on when the alien child grows up and reproduces. This is possibly the simpilest of all life states. Advantages include a unique skintone and facial features. When an alien sim is born a different cinematic is used. An alien teenager can apply for an alien scholarship for college.
Zombies: Released with University. If a Sim bids between $998 and $4127 when using the Ressurect-O-Nomitron, the Sim they are reviving returns as a zombie. He or she returns with a blue-ish skintone, distorted facial features, and a set zombie personality. Zombies cannot walk, skip, or run-they move with a zombie "shamble". Skill points are also lost. Zombies do not age unless a teen zombie chooses to go to college and do not die of old age. Occasionally a sim may react in a disgusted way when a zombie enters a room.
Vampires: Released with Nightlife. If a Sim is bitten by the "Grand Vampire" or a pre-bitten sim, he or she joins the world of the undead as well. Initially sims are bitten only if they have a high relationship with the vampire, however once one sim is bitten by a vampire any sim that comes into contact with a vampire has a risk of being bitten, wether or not they are a playable sim and regardless of the relationship with the vampire. Other sims can also influence a vampire to bite another sim.

Once bitten, the newly created vampire can bite other sims. Vampires can transform into bats and fly around and 'stalk'. At night their motives don't decay, however, if they are outside in the sun their motives drop very quickly (with smoke), eventually leading to the vampire's demise. Vampires do not have a relfection in the mirror. If one is used, the vampire will react and their comfort bar will drop. Occasionally vampires will hiss or go 'bleh' if no other action is currently underway. Vampirism can be cured with vamprocillin-D which is bought from the matchmaker.

Servos: Released with Open For Business. Sims can build robots on the robot creation bench which becomes a member of the sims family. If they have a gold talent badge in robot making that is. A servo has different needs to a normal sim. Begin a robot they don't need to eat or sleep, however they do need power, which can be attained by sleeping or 'recharging' in the sunlight. Should a servo's power go into red, the servo will 'go beserk' and need to be fixed by a sim with a high mechanical skill.
Werewolves: Released with Pets. Occurs when sim is bitten by leader of the pack. The leader has yellow glowing eyes and comesto your lot at night. Werewolves are sim by day and wolf by night. Being a werewolf also slowly alters statistics such as skill points (body) and personality (playfullness). It also lets you train dogs faster.
PlantSims: Released with Seasons