Wikipedia describes this work as an operatic parody of Richard Wagner's opera. Most experts consider the animated short as Director Chuck Jones' magnum opus. Look at the following analysis of "What's Opera, Doc?"
What's Opera, Doc? (1957) takes us still more deeply into the world of parody. Here Jones and arranger Milt Franklyn offer a grandiose skewering of Wagnerian themes and conceits. With his cries of "kill the wabbit" unforgettably grafted onto the characteristic dotted rhythm of the "Ride of the Walküres" from Wagner's Ring, Elmer's pursuit of Bugs is raised to a maniacal pitch. Whereas Stalling's score for the Rossini project confined itself almost exclusively to a single overture, Franklyn juggles a pastiche of favorite themes, not only from the Ring, but also from Flying Dutchman and Tannhaüser. The famous Venusberg ballet from the first act of the latter opera becomes a ridiculous parody of a Wagnerian love duet, complete with an overstuffed horse and its gigantic backside...
When I was young, I thought the cartoon was funny. I have no intention of doing an analysis of What's Opera, Doc? Being funny - I'll just leave it at that but some pundits revealed the cartoon's deeper meaning - how it uses opera tools to make fun of opera itself. This is truly a work of a genius and deserves the greatest cartoon tag.
For the musically curious, cartoon sound tracks served as a point of entry into distant musical and timbral worlds that young viewers might never have otherwise encountered, much less understood. And even if some will lament the transformation of operatic and symphonic standards into slapstick entertainment, we must concede that decoding the layered meanings of these cartoons actually requires remarkable imagination and insight. Listening today to the sounds of these decidedly silly cartoons, we can nevertheless marvel at the artistry and wisdom that foolishness can sometimes inspire...
For a spoof to really work, one must have in-depth knowledge and appreciation of the art that he lampoons.
For example, Willie Nepumoceno impersonates Filipino politicians and other big shots. He does it so successfully because of the in-depth knowledge he has on people he copies. His characterization is deep and most likely what the real person would say in the first place. Poohkyaw's impersonation of Manny Pacquiao however is stupid, tasteless and racist - copying Manny's regional accent is not enough to be funny unless one is fond of garbage entertainment.