How to make transforming bodies?

[exxa]

I want to make superhero characters who can transform between two different bodies, similar to the Hulk. The only transforming occults I’m aware of are aliens, vampires, and mermaids. Do I just need to make an alien and download a tuning mod to get rid of the alien voice and traits (such as other sims reacting to alien)? These are human characters, so I really don’t want people to have occult reactions to them.