In The Sims 2, an Alien can be created using the boolProp testing cheat. Entering “boolProp testingCheatsEnabled true” activates the game’s debugging features; in Create a Sim, pressing Shift+N can unlock normally hidden genetic options, including alien skin and eyes.
Alien Sims are a life state in The Sims 2, although they are not normally available through the standard Create-a-Sim menus. Players can also encounter aliens through alien abductions, usually involving repeated telescope use. In that route, a Sim may return from an abduction pregnant with an alien baby, depending on the Sim’s gender and game configuration.
The other choices belong to different parts of The Sims series or later expansion content. PlantSims were introduced with The Sims 2: Seasons, vampires with Nightlife, and werewolves with Pets, but the standard boolProp Create-a-Sim debug method is chiefly associated with unlocking alien genetics. Because testing cheats can cause unexpected game behavior, experienced players generally disable the cheat after use.