Hybrid

A hybrid is when a sim has more than one different life state, for example, a vampire alien. These hybrids can add a new dimension to the game, adding new difficulties and similarities.

Anything alien
The aliens life state is just a skin tone and different genetics - therefore it can be coupled with any other lifestage, this usually results in the creature having a different colour skin tone, for example a vampire alien will have a turquoise skin tone. The only exception is servos

Anything zombie
Again, the zombie life state is just a skin tone, a few autonomous reactions and a funny walk, therefore, with the exception of servo, it can be mixed with anything else.

Vampire Servo
Servo can become vampire, meaning as well as dying in water, he'll also die in the sun. This is a bad thing, generally, since all Servos required the Sun to recharge.