The "Utsutsu Makura" (Real Dream Pillow) is a gadget from the manga *Doraemon*—or so it might seem.
It appears in the episode of the same name (included in Volume 5 of the Tentom虫 Comics). It is said to be a gadget that swaps dreams and reality.
The story begins with Nobita waking up early and finishing all of his summer homework. In that world, Doraemon tells him, "Isn't this a dream?" When Nobita wakes up, he finds himself on the last day of summer vacation, and he hasn't done his homework at all. Distraught at having his wonderful dream ruined, Nobita cries and wails. Feeling bad for him, Doraemon pulls out the "Utsutsu Makura." Nobita falls asleep again using the pillow.
When he wakes up again, just like in his previous dream, his homework is done. Nobita goes to school, but even though he isn't late and has completed his homework thoroughly, no one will believe him. Annoyed, Nobita uses the pillow once to return to the original reality, but doing homework is still a hassle.
So, he uses the "Utsutsu Makura" a second time to experience a reality where he has become a genius. As a genius, Nobita is admired by everyone, swarmed by reporters, and becomes someone the Prime Minister himself wants to meet. However, a spy from Country XX appears before this version of Nobita, targeting his life. Panicking, Nobita tries to turn his current situation back into a dream. Even as he is knocked unconscious by the spy, he somehow manages to use the pillow successfully…
Nobita wakes up, shaken awake by Doraemon. He seems to have narrowly escaped danger, but when he checks his homework, it isn't done. Panicking, he leaps at Doraemon demanding him to bring out the "Utsutsu Makura," but Doraemon has no idea what such a gadget is, and moreover, there is still more than half of summer vacation left.
Confused, Nobita no longer knows which of the realities he has experienced is actually a dream.
This is seriously terrifying. Isn't there a possibility that this final world is just "a dream world where the Utsutsu Makura doesn't exist"?
It's less scary and more deeply unsettling.