Final answer:
The nickname "Cav and Pag" refers to the opera double-bill pairings of "Cavalleria Rusticana" and "Pagliacci," which are notable one-hit wonders in the genre of opera.
Step-by-step explanation:
The characters "Cav" and "Pag" refer to the operas Cavalleria Rusticana and Pagliacci, which are commonly presented together as a double bill in the genre of opera. They are so well paired that together they have their own nickname: "Cav and Pag."
The operas are known for their intense drama and are recognized in the opera world as popular one-hit wonders. Unlike other genres such as rock and roll or musical theater, these operas are celebrated for their musical composition and have stood the test of time in the opera repertoire.