Tenant's Spare Key
Wondrous Item, Rare (Requires Attunement by a Rogue)
While holding the key against a nonmagical lock, you can take a Magic action to learn whether that lock has been unlocked in the last 24 hours. If it has, you also learn how long ago it was last unlocked, to the nearest hour. If a creature unlocked it, you learn whether the creature was Small, Medium, or another size; otherwise, you learn that no creature unlocked it. The key has three uses of this property, and expended uses are restored at dawn.
Curse. Using the key's property curses you. While cursed, subtract 1d4 from Dexterity checks you make with Thieves' Tools to unlock a lock you have previously unlocked. While you aren't cursed by this item, you can voluntarily end your Attunement to it. While cursed by this item, you cannot voluntarily end that Attunement, and the curse persists if Attunement ends another way. Remove Curse cast on you ends the curse and your Attunement to this item.