To get special sim skins (such as vampire and alien) :
Do the "boolprop testingcheatsenabled true" (no Quotaion marks) cheat and after that go into create-a-sim
Now press shift N and you will unlock a heap of new outfits, hairstyles, etc.
Chat with our AI personalities
you have to buy the costume trunk(aspiration unlock)and put on costume then select take off
You can't really be a mermaid or fairy on Sims 2. But go on modthesims2.com or go to a downloading place for sims 2 and there should be a mermaid or fairy COSTUME. Download that and go to one of the stores in the town. The costume should be there and so buy it. Then go to your dresser at home and put it on.
No you can't.
i figured it out! you go to a mirror and put on a different costume makeup and then when you take that off it will be gone :) (try it with a not-downloded costume makeup)
Go to the salarium and get a tan