Chrysalis

You create a magical cocoon around yourself. The cocoon can be on the ground or suspended above the ground. It is considered a Large object with an AC of 10 and 5 hit points. While inside the cocoon you have full cover against effects that originate from outside it, and the atmosphere is comfortable and dry, no matter the climate outside. The cocoon is opaque from the outside, of any color you choose, but is transparent from the inside. Spell and other magical effects can't extend through the cocoon or be cast through it. If the cocoon is reduced to 0 hit points, the spell ends and the material component used for the spell is detroyed. After completing a long rest while inside the cocoon, you gain the result of 1d10 + your spellcasting modifier in temporary hit points. 

At Higher Levels. If this spell is cast with a spell slot of 4th-level or higher, you gain a set of spectral butterfly wings after finishing a long rest in the cocoon. These wings grant you a fly speed of 40 feet and last until you lose all of your temporary hit points granted by this spell.