Doctor Strange in the Multiverse of Madness Description:

In the Gap Junction, the space between universes, America Chavez and Defender Strange race to the Book of Vishanti while attempting to evade a Ribboned Creature. Strange’s attempts to contain the monster prove futile, leading him to attempt to steal Chavez’s power of multiversal travel, while knowing that the process would kill her. However, the demon kills Strange during the process, and Chavez, in fear, inadvertently opens a portal to Earth-616 which she and Strange’s corpse fall through.