concentration, 1 hour/mana
As two actions, you take possession of a willing creature that you can touch or see within 10 meters (creatures warded by a protection from evil and good or magic circle spell can’t be possessed).
Your soul moves into the target’s body. Once you possess a creature’s body, your body falls into a catatonic state as your soul leaves it and enters the body of the creature which you control. Your game statistics are replaced by the statistics of the creature, though you retain your personality and your Intelligence, Wisdom, and Charisma. You retain the benefit of your own class features. If the target has any class levels, you can’t use any of its class features.
Meanwhile, the possessed creature’s soul can perceive using its own senses, but it can’t move or use any actions other than to make a Will saving throw as an action on its turn, ending the possession on a success.
While possessing a body, you can use an action to return from the host body to your body if it is within 20 meters of you. If the host body dies while you’re in it, the creature dies, and you must make a Will saving throw against your spell save Difficulty.
On a success, you return to your body if it is within 20 meters of you. Otherwise, you die.
Augment
Unwilling. You can expend 1 additional mana to target an unwilling target. The duration changes to 1 minute/mana and the target must succeed on a Will saving throw or you possess it for the duration. If you or creatures that are friendly to you are fighting it, it has advantage on the saving throw.
Each time the target takes damage, it makes a new Will saving throw against the spell. If the saving throw succeeds, the spell ends.
Creature. You can expend 1 additional mana to target any creature.