For 10 points, identify this Classical composer and child prodigy who wrote "Eine kleine Nachtmusik".
Franz Sussmayr completed this composer's unfinished Requiem after his death. This composer of the "Jupiter" Symphony wrote an opera in which Leporello sings the Catalog Aria and whose title character goes to hell, Don Giovanni, as well as a work in which Tamino defeats the Queen of The Night, The Magic Flute. For 10 points, identify this Classical composer and child prodigy who wrote "Eine kleine Nachtmusik".
Franz Sussmayr completed this composer's unfinished Requiem after his death.
Wolfgang Amadeus {Mozart}