A rare type of mold that can be brewed into a healing potion via the Brewing Patch (assuming an implementation in which no existing molds are brewable into healing).

Dipping a unicorn horn in acid dissolves and destroys the horn, producing a potion of healing.

Diluting full healing potions turns them into undiluted extra healing; diluting extra healing turns them into undiluted healing. Though this may create weirdness where, for instance, a milky potion gets diluted and turns into a brilliant blue potion, and then gets diluted again and turns into a golden potion.