Oh, what an interesting question. Hmm... if I could, I would choose the Lie 800 potion, which is a potion that makes lies come true. I have a plan to replicate what Nobita did in the last part of the movie Stand By Me, so I could have my very own Doraemon to grant all my wishes afterward. I'm sorry if it seems like a lame answer, but as a Doraemon enthusiast, I've given it a lot of thought. How about you? What would you choose?