mystical is unlocked by an event upgrade using essence, gained overtime by discovered potions. Potion shelf upgrade specifically.
Mystical is a potion ingredient, the mystifier and bundle require topaz, a gem unlocked after unlocking the events, gained when an event is NOT going on at the same rate as other gems
Potato water and Mystical water are not the same thing. Potato water is tied to a later upgrade while Mystical is tied to the current event
