Can aliens become vampires?

Hey @MysticcSimmer, welcome to the forums! Since this thread is discussion old I am closing it but feel free to join in on the discussion in active, on-going topics! :smile:

Not without a mod.

Alien life state is it's own thing, can't be an alien vampire, for example.

Ok thank you, but three more questions:
What kind of mod?
Why does the alien want to be one
even though it's impossible in the game?
If my alien has a baby with a female vamp will the spawn be a alien vampire or either or?

http://nraas.wikispaces.com/
You need MasterController and Hybrid.

Some of the wishes were not properly coded. There should have been an exception included so that other Occults couldn't roll it.
There were a few wishes that should never have been included in the game - like becoming an Imaginary Friend or a Unicorn. These are also impossible. I'm not a programmer, but that may also have been a result of exceptions that should have been included.

When you cross two Occult types (or an Occult and a Normal Sim), you are supposed to get one or the other.
I'm not sure this is true or random occurrence in my game, but it seems like Alien genetics are dominant.

Alien DNA is ALWAYS passed on. It's different from other occult states that way, which is just a yes/no hidden trait. Technically, aliens are Sims with their own unique DNA that can blend with human DNA.
The game calculates the 'percentage' of alien DNA that a child has, and the powers are stronger if they are more alien. In a few generations the alien powers are gone.

My alien had a plantsim baby who turned alien the moment he pulled him up out of the incubator due to genetics transfer. Apparently the parent's genetics transfer to the plantsim baby the moment they are 'harvested'.
This doesn't happen with other occults when they get a plantsim baby - the baby will always be a plantsim. Having the 'plantsim' hidden trait means they can't have another occult hidden trait. (Just like they can't have both 'lucky' and 'unlucky', etc.)

I think you're right about the exceptions. I'm not much of a programmer either, but I have done enough messing around in Sims 1 to know that you have to build in checks for every action. Forget one, and you get stupid things like stretchy pets doing 'human' things, or stretchy toddlers pushing elevator buttons in LN. Or weird wishes.