By drinking from an overly sugary potion you gain the power of a Magical Girl Mascot.
*Your body changes to that of a Magical Girl Mascot, or Puchuu if you want to be technical. You are now small and cute and look like a plushie toy or a pokemon. The details are up to you but you have to follow this theme.
*Your new body is highly resistant to all forms of damage, and have a healing factor that will bounce you back to full health after a few hours of resting if you ever need it.
*You have an unmatched magical potential and the reserve of magical energy big enough to back up this fact. However, you will only know a limited repertoire of exclusive defensive and support spells at first, you may create more later.
*You can create magical girls from the young members of a sapient species that you encounter, provided they have the potential to become one, a characteristic that is more often found in young females.
*You can detect individuals with the potential to become magical girls if they are in close proximity to you, and you can detect individuals across a large area if you meditate with this purpose on mind.
*A magical girl is created through a bonding process that give you absolute ownership of the girl's entire beung (you may share this fact or not), the bonding process can take any form you want, and you may choose to give something to the girl in exchange, like a wish. Be warned that the bond does not give you power to fulfill the wish, you must use it your own power to do so.
*You may choose which 'system' a magical girl's grow will be following. This is tied to the power and magic, and it will dictate how she will grow in these aspects. They can be like a level up system, or an achievement based system, or a visible skill tree, or many others. You may choose which one in the moment of the bonding or leave it on automatic and let fate decide, whatever you choose you can't change it afterward.
*The potential of a magical girl will dictate how strong she will be in her first transformation, you can artificially enhance this initial strength at the cost of some of her potential, meaning you can get a strong magical girl right out the gate at the cost of lessening her ability to become stronger. You may also do the opposite, and cripple a magical girl's initial powr in exchange for an increase in her potential. At the most extreme example of this you can create a country-destroying girl who can't become stronger no matter what she does, or a utterly useless girl with the potential to achieve godlike levels if she work hard enough.
*You can control the relationship between a girl's untransformed state, and her transformed one. The standard relationship is that the untransformed state is the same as it was before the bonding, while the transformed one looks the same but carries all the new strength and magical power. You may choose to change that at any way you wish.
*You may choose to add lewd aspects to your magical girls, going from the entire process having being deeply lewd, like magical girls from a hentai setting, to having only minors or singular aspects being lewd.
*Each magical girls you create belongs to you on a fundamental level, this bond can not be broken. At the passive level, it will make the girl loyal to you, and you can easily turn this loyalty into friendship and with a bit more effort even true love. At the active level, you can easily use your magic on or through your girls no matter what defense they puts, you can give orders they can't refuse, put their mind into s highly suggestive form trance to mold and shape their memories and personality at your will, and many many more.
*Each girl you create increase your personal power at some level, this may come in the form of completely new abilities manifested on a whim, or a new magical insights related to your girl's personal magic.
*You have a 'sixth sense' that is attuned to the larger multiverse; this sense will tell you where you and your girls are needed the most. Once you located the world you may travel to it.