There are 11 kinds of supernaturals in the SimVerse:
Supernaturals are the direct result of splicing alien DNA of some kind with Sim DNA. Successful splicing results in a supernatural. Unsuccessful splicing typically results in EXCES, a disease that slowly eats away at the Sim’s body because the body rejects the alien DNA.
It is believed aliens are responsible for the supernaturals in the SimWorld due to experimentation – werewolves, fairies, vampires, witches, genies,ghosts,mummies, mermaids, and PlantSims. Zombies are considered a side effect of late stage EXCES. Bigfoot is also believed to have existed at some point on Simterra, but hasn’t been seen for a long time. Theories include he was taken back to Xenosa or he died. Some Sims also believe the Grim Reaper is an alien from the planet Xenosa, but this hasn’t been proved.
Zombism is caused by EXCES. EXCES is a disease caused by the body’s rejection of alien DNA. Read more here.
Ghosts are temporarily caught in time-space, and are the only supernaturals who are not altered by the Xenosi.
No one really knows what causes a mummy to come to life.
PlantSims came about in a strange way, through the genetic manipulation of plants, Sims, Xenosi, and possibly Atlântidans. PlantSims are among the rarest of supernaturals, and are often face discrimination.
The Simborg are a term applying to Simbots, Plumbots, and Imaginary Friends. They are the only supernatural that are created by Sims. However, bringing a “bot” or “imaginary friend” to life requires Xenosi technology.
Werewolves are considered the oldest supernaturals as they were first discovered in Deutsimland shortly after the Simmians arrive on Simterra. Werewolves are the direct result of gene splicing between the Lykonians and Sims.
Zombism is a result of EXCES. Read more here.