Source: The Book of Many Things

Armor (studded leather), rare (requires attunement)

This black studded leather armor bears a red sheen. While wearing this armor, you can use a bonus action to summon a projection of yourself in an unoccupied space within 30 feet of yourself. The projection is a translucent copy of you that has immunity to all damage and conditions, and you can make attacks and cast spells with a range other than self as if standing in the projection’s space. The projection disappears at the end of your turn. Once you use this bonus action, it can’t be used again until the next dawn.

Curse. This armor is cursed, and attuning to it extends the curse to you. As long as you remain cursed, you’re unwilling to part with the armor. Taking it off fails to end the curse. While cursed in this way, you feel disconnected from your body, continuously hearing whispers that call for you to join them. Whenever you finish a long rest while cursed, you must make a DC 11 Charisma saving throw. On a failed save, your soul is drawn from your body and trapped in an object on a different plane of existence. The object and location of this object are chosen by the DM (but might be the House of Cards; see chapter 18). While your soul is trapped in this way, your body is inert and doesn’t age or require sustenance. Destroying the object frees your soul; otherwise, only a Wish spell can restore your soul to your body.