Separate Physique for Dark Forms and Alien Disguise

[PabloHoney]

I know it was possible, at one point, for the alien disguise to have different muscle and fat compared to the main form.

 

I thought having a fat main sim become a slim and fit sim once they enter dark form or alien disguise would be cool.

 

Is there an existing mod that gives that option?

 

Hope someone could help. Thank you.