Bookmark of Eldritch Insight

This cloth bookmark is inscribed with blurred runes that are hard to decipher. If you use this bookmark while researching ancient evils (such as arch-devils or demon lords) or otherworldly mysteries (such as the Void or the Great Old Ones) during a long rest, the bookmark crumbles to dust and grants you its knowledge. You double your proficiency bonus on Arcana, History, and Religion checks to recall lore about the subject of your research for the next 24 hours. If you don't have proficiency in these skills, you instead gain proficiency in them for the next 24 hours, but you are proficient only when recalling information about the subject of your research.