Pagliacci is an opera written by Italian composer Ruggero Leoncavallo. The plot focuses on a clown who murders his wife and her lover in a fit of jealousy.
It was almost certainly plagiarised from the French play La Femme de Tabarin.
This is probably the point at which the more philosophically minded would ruminate about originality and art, but most of you are still trying to sound-out the pronunciation of “Pagliacci.”