Wondrous Item, very rare (requires attunement)
This fine garment is made of silver silk that appears invisible at some angles. While wearing it, you gain the following benefits:
- You have resistance to necrotic damage.
- You can move through other creatures and objects as if they were difficult terrain. You take 5 (1d10) force damage if you end your turn inside an object.
- Once per day you can use an action to attempt a possession. You target one humanoid that you can see within 5 feet of you. The target must succeed on a DC 13 Charisma saving throw or be possessed by you; you and the target are incapacitated, and the target loses control of its body. You now control the body but don't deprive the target of awareness. You can't be targeted by any attack, spell, or other effect, except ones that turn undead, and you retain your alignment, Intelligence, Wisdom, Charisma, and immunity to being charmed and frightened. You otherwise uses the possessed target's statistics, but don't gain access to the target's knowledge, class features, or proficiencies.
The possession lasts until the body drops to 0 hit points, you end it as a bonus action, or you are turned or forced out by an effect like the dispel evil and good spell. When the possession ends, you appear back in your body.
Notes: Resistance: Necrotic, Control, Buff, Movement, Outerwear
Is this supposed to be almost identical to the Magic Jar spell? If not, you might want to clarify what happens to the host consciousness if the body takes damage to 0 hp or if your own body takes damage to 0 hp while your character's consciousness is outside of it.
That ability was copy and pasted from the ghost stat block. I will definitely change the wording to make it more clear.
I would also go through the Magic Jar spell in the PHB and compare that with the ghost in the MM. I don't have the latter myself.