Occult is the blanket name given to all non Sim lifestates in the Sims 3, the game recognises them as simbots or mummies, not as hybrids. TS3 Hybrids are basically broken occults. It was the same in the second, which, by the way, went waaay overboard with (proper) hybrid possibilities (such as vampire plantsims) Why do you think there is so few intended hybrids (anything+ghost, really) in the Sims 3? Disappointing that Imaginary Friends can`t become hybrids with either vampires or mummies, though. Also, children of vampires/imaginary friends are true, non glitched occults as far as I am aware, although I don`t doubt that there are bugs that change that.