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The Flask is an item in the PC release of Mario's Time Machine. It contains some part of the rabies vaccine that Louis Pasteur and Pierre Paul Emile Roux were working on. According to Mario's Time Machine, in 1885, as the two near the vaccine's completion and are about to test it on a human who was bit by a rabid dog (nine-year-old Joseph Meister, although he is never named in-game), Bowser travels back in time and steals the Flask. He then places it in his museum alongside all of the other items he stole throughout time. Later, Mario takes the Flask and travels back in time himself to Paris to return it to Louis, without knowing that the Flask belongs to him. Mario then shows it to other people within Paris, and Pierre Paul Emile Roux recognizes its importance and shouts at Mario to bring it to Louis immediately. After absolutely confirming its importance, Mario brings the Flask to Louis, who immediately begins to use it to synthesize a vaccine.