The Sims 3: Seasons introduces the alien friends and lovers that your sims can encounter. It’s really easy to get abducted, which might actually be a pain if you don’t want it to happen. Both males and females can be abducted as well as have the chance of coming back pregnant with an alien baby. You can also work up your relationship with aliens and eventually ask them to move in.
To increase your odds of getting abducted, you can carry moonstones and have them around your house, make your sim have high logic skill points, and use a telescope/ look at the sky at night.
In no time, you’ll be getting kidnapped from your home by a strange alien life form. No big deal. Congratulations, I guess?