Spell Weaver Brew (5e Equipment)
From D&D Wiki
This brew is created from Elder Wizards who have a distaste to non-spellcasters and their violent ways. But also as a way to appreciate those who partake in Arcane practices. This potion looks appears as a purple liquid in a gem-shaped bottle. But when touched by a spellcaster, the potion starts to stir itself from within the bottle. The contents now appear as purple, sparkling sand rapidly stirred across the bottle.
When a spellcaster drinks this potion, they regain all of their expended spell slots. When a non-spellcaster drinks this potion, they have vulnerability to all damage from spells and making saving throws against spell effects with disadvantage.
This liquid tastes like sugar water to a spellcaster but tastes like salt water to a non-spellcaster.