Change Weight Spell

Simae Pondus is a new spell that allows the user to change weight of sims or make them athletic.Once you learn this spell,you will have 3 options (spells) under the simae pondus category.
1) Slimify: Make yourself or others slim.(If fails it will make you or target fat.)
2)Fatify: Make yourself or others fat.(If fails it will make you or target slim.)
3)Athleticus: Make yourself or others athletic.(If fails it will make you or target fat.)
This is level 3 practical spell.
You can learn this spell by dueling,practising or from the tome.
If you have any suggestions for custom spells,please let me know.