A glass syringe with viscous white liquid flowing in it.

when a creature is injected with the liquid, they become a hill giant, inheriting ones stats and abilities, they also "lose their mind" forgetting about their past life, and aiming to only consume humanoid creatures. this effect is permanent except through a wish spell.

consummation by means other than injection can have... adverse effects...

Notes: Shapechanging, Consumable, transmutation