Source: Tal'Dorei Campaign Setting Reborn

Weapon (dagger), rare (requires attunement)

This silver stiletto blade bears intricate grooves that spiral from its tip to its ivory hilt and handle. You gain a +2 bonus to attack and damage rolls made with this magic weapon.

As an action, you can place the point of the blade into any keyhole and seal it shut. A keyhole sealed in this way can't be unlocked until this dagger is placed into that keyhole once more (though a sealed door or container can still be broken, bypassing the lock). Sealing a keyhole unseals any keyholes previously sealed with this weapon.