Aliens are already in the packs base. <br />Zombies require the University expansion pack. <br />Vampires require the Nightlife expansion pack. <br />Servos require the Open for Business expansion pack. <br />Werewolves require the Pets expansion pack. <br />Plant sims require the Seasons expansion pack. <br />Bigfoot requires the Bon Voyage expansion pack. <br />Genies requires the Free Time expansion pack. <br />Witches requires the Apartment Life expansion pack.
