Alchemical Anti-Weave

You create an alchemically pure catalyst against magic. This concoction remains potent for the spell's duration, as long as you maintain concentration. You can drink this potion as part of the same action of creating it, or it can be given to an ally who can drink it as a bonus action. Drinking it grants the user magic resistance. Once per turn when the drinker damages a creature, that creature must make an Intelligence saving throw. On a failure they take 6d6 psychic damage and lose the ability to cast spells or use magical effects until the end of their next turn. Any spell or magical effect that the creature was concentrating on is lost. On a successful save they take half as much damage and suffer no other ill effects.