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 skintone and different genetics- therefore it can be coupled with any other lifestage, this usually results in the creature having a different colour skintone, 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 skintone, a few autonomous reactions and a funny walk, therefore, with the exception of servo, and the alien,  it can be mixed with anything else.