Bone Cocoon

You conjure a cocoon made of solidified bone and cartilage, a desperate attempt to protect their life. Choose one unconscious creature that you can see within range, it is engulfed in the osseous formation. While in the cocoon, the creature can't be damaged by attacks originating from the outside, has total cover, is considered restrained, and makes death-saving throws at advantage.

The cocoon has 45 hit points, an AC of 11+ your spell-casting modifier, it has resistance to cold, fire, and necrotic damage, and immunity to poison and psychic damage. If your concentration ends or the cocoon is brought to 0 hit points it is destroyed and the spell ends.