Sans

Sans is the brother of Papyrus and a major character in Undertale. He first appears in Snowdin Forest after the protagonist exits the Ruins. He is the deuteragonist of the Neutral and True Pacifist routes, in which he keeps an eye on the protagonist throughout the game. He is also the final boss and heroic antagonist of the Genocide Route, in which he confronts the human in the last corridor. Sans is lazy, often sleeping on the job and taking breaks. His laziness is a combination of fatalism and apathy, as he is aware of timeline resets. Conversely, he suggests that this knowledge could be "a poor excuse for being lazy. He enjoys being mischievous. Sans primarily acts this way towards those he is in good terms with. His antics range from an assortment of illogical, juvenile, and slightly inconvenient pranks. Examples include Sans "selling fried snow," using whoopee cushions, sharing an unscrewed ketchup bottle, and eye paint on a telescope.