Undead Phylactery

You project your spirit from your body as your spirit becomes untethered from your physical form. The body you leave behind is unconscious and in a state of suspended animation. It no longer ages and is immune to magical ageing.

Your spirit resembles your mortal form in almost every way, replicating your game statistics but not your possessions. Any damage or other effects that apply to your spirit or physical body affects the other. Your spirit can remain outside your body for the duration, or until your spirit drops to 0 hit points or dies. As a spirit 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. As a spirit you gain the Condition Immunities for Charmed, Exhaustion, Frightened, Grappled, Paralyzed, Petrified, Poisoned, Prone, and Restrained until you take physical form again.

If you concentrate on this spell for the full duration, your spirit remains outside of your body until you reenter your body by moving within 5 feet of it. Additionally, your body no longer receives the same damage or other effects that your spirit takes or vice versa. If your spirit receives fatal damage you do not roll death saving throws, you instead disappear. If your body is still active, in 1d10 days or 1d100 days if your spirit and body were on separate planes, your spirit reforms within 5 feet of your body the Undead Phylactery regaining all your hit points and your spirit becomes active again. If your body is destroyed your spirit remains unaffected until your spirit receives fatal damage resulting in your death.

If dispel magic is successfully cast on your body or your spirit, your spirit instantly reenters your body and the spell ends. You are unaffected by dispel magic if your body is already destroyed.

If the spell has lasted for the full duration your spirit can now use the Action Possession (Recharge 6): One humanoid that your spirit can see within 5 feet of it must succeed on a Charisma Saving Throw or be possessed by the spirit; your spirit then disappears, and the target is incapacitated and loses control of its body. Your spirit now controls the body but doesn't deprive the target of awareness. Your spirit can't be targeted by any attack, spell, or other effect, except ones that turn undead, and it retains its alignment, Intelligence, Wisdom, Charisma, and retains immunity to being charmed and frightened. It otherwise uses the possessed target's statistics, but doesn't gain access to the target's knowledge, class features, or proficiencies. The possession lasts until the body drops to 0 hit points, your spirit ends it as a bonus action, or your spirit is turned or forced out by an effect like the dispel evil and good spell. When the possession ends, your spirit reappears in an unoccupied space within 5 feet of the body. The target is immune to your spirit's Possession for 24 hours after succeeding on the saving throw or after the possession ends.

If your original body is ever destroyed, after your spirit possesses another humanoid you can spend a long rest performing a ceremony to turn this host into your new Undead Phylactery. At the end of the ceremony your host must make a Constitution Saving Throw. On success, the ceremony fails and the host makes a Charisma Saving Throw at advantage to end the Possession. On failure, your spirit exits the host which becomes unconscious and in a state of suspended animation becoming your new Undead Phylactery. If dispel magic is successfully cast on your spirit or your new Undead Phylactery, your spirit is unaffected but your Undead Phylactery is awakened and no longer under your control.