The Odincasket was created by Falki while Odin was still the ruler of Asgard. It was designed to facilitate the Odinsleep so that Odin would spend less time in it. It contains enchantments that create a state between life and death, much like mortal doctors will induce a coma to allow someone who is wounded to heal more quickly. Also, once closed from within, it can only be opened from the inside, and no force of man or gods can force it open from the outside.