Arcane Self

As you reach 0 hit points, your spirit and your inner magic detach from your body and create an arcane spirit.
In arcane spirit form, you heal to your maximum hit points and you become incorporeal.

Moreover, while in this form you gain the following benefits and drawbacks :

• you gain a flying speed equal to your walking speed,
• you can enter and occupy the space of other creatures,
• you don't need to breath,
• you gain resistance to non magical bludgeoning, slashing and piercing damage,
• your AC become equal to 13 + your spell casting modifier,
• you can’t cast level 1 or higher spells,
• you can't activate magic items, use objects or wield weapons, 
• your dead body is stabilized,
• when your dead body should take damage, your arcane spirit take twice those damage instead.

If you reach 0 hit points in arcane spirit form, you’re dead.

If your body regains hit points, if your arcane spirit is targeted by a dispell magic spell, or at the end of the duration of the arcane self spell, your arcane spirit rejoins your body. Your hit points become equal to the hit points of your body and you no longer experience the other benefits and drawbacks of being in arcane spirit form.