Gu Yu died suddenly while playing a game and traveled to a parallel universe. Gu Yu found that he had traveled to the world of Undertale. Then, Undertale was released, and he became the only player who knew the plot of the game. Toriel: The underground world is too dangerous. You should stay in the ruins. Sans: Gu Yu, I came up with another cold joke. Papyrus: I've thought of a new pasta, human, come and try it. Gu Yu: No! That stuff will kill you if you eat it!
