Yu-Gi-Oh! Destiny's Recompense

Post-DSoD. Kaiba's experiment with the space elevator fails. He can't access the afterlife, and wakes up in a hospital, disappointed. He is wrong, however. The experiment succeeded, just not in the way he hoped... He was able to open a portal to the afterlife; it's just that he wasn't able to get in. Something, however, managed to get out...