after soaking in the vials for so long the vials slowly dissolved all physical parts of Marys body and then the magical energy of the vials fuses with Marys soul to turn Mary into a living slime girl made out of the transformation vials.
Mary is now a pinkish colored slime girl with E cup tits, a gigantic ass, and no organs, bones, flesh, or blood. although because Mary is made up of the transformation liquids any living thing that touches her will be randomly transformed neither Mary, the person being transformed, or anyone else has any comtrol over what they will transform into.
As Marys soul has fused with the transformation liquid Mary now has some of the desires that were given to the liquids such as the desire to transform herself and other people into beasts that desire nothing but sex and mary had the perfect first victim.