Elmer Fudd is trying to get to sleep one night. Unfortunately his rest is interrupted by Sylvester the cat, who has chosen that evening to take a perch on a fence and give a concert. Elmer tries to make Sylvester shut up, only to grow increasingly frustrated as Sylvester repeatedly escapes him.
- As Elmer goes up to the roof to hit him, Sylvester gives his sheet music to a dopey-looking tabby cat who, judging from the way he turns the sheet around, doesn't seem to know how to read music or is going to sing off-key and in a Simpleton Voice. Then he (she?) sings "Carissima" in a beautiful soprano voice.
- Sylvester's Spike Jones-esque rendition of "Angel in Disguise" includes two such gags. First he pulls out a line of firecrackers (as seen in the page image), three large ones and a small one. The big crackers pop underwhelmingly, while the smallest one goes off in a mighty explosion. Second, Sylvester pulls out a vase and a hammer and rears back as if to smash the vase, but instead taps it lightly.
- Bowdlerization: When this cartoon aired on the WB!, the three times Elmer runs down the steps (which are slippery from grease) and steps on tacks when trying to stop Sylvester from singing were cut.
- Cat Concerto: Sylvester is determined to give one, singing horribly, and Elmer is determined to stop him.
- Cats Have Nine Lives: And to Elmer's horror, all nine of Sylvester's lives go up to heaven with him at the end.
- Forgotten Trope: The alum gag. Sylvester's head shrinks to tiny size when he drinks the alum-laced milk Elmer sets out for him.
- Letting the Air Out of the Band: Sylvester brings in an orange opera singing cat to take his place when plotting a grand scheme. After Elmer Fudd silences the cat with a blow to the head—just as he hits the high note—we hear this effect directly.
- Oddball in the Series: One of the only Sylvester the Cat cartoons where Sylvester wins, although he does have to die to do it.
- One-Man Band: One of the many ways that Sylvester infuriates Elmer is by performing as a one-man band in Elmer's bedroom.
- Rapid-Fire Comedy: The "Angel in Disguise" number, with Sylvester peppering his performance with sight gags delivered at breakneck speed, some too fast to see at normal speed.
- Shoe Slap: Elmer scores a direct hit on Sylvester with a thrown shoe.
- Shout-Out: Sylvester's swan song is "Angel in Disguise" done in the style of Spike Jones' recording of "Cocktails for Two", complete with Sylvester singing the song straight (without his lisp), then launching into the "wild" version with sound effects, horns, tubas, and banjos. Side note: Mel Blanc himself did a few recordings with Spike, including a hiccuping verse on "Clink, Clink, Another Drink".
- Standard Snippet: Typical of the cartoons of the era, this short made extensive use of Warners' music publishing library. Among the Warner hits and obscurities Sylvester sings are "Some Sunday Morning" (introduced in the 1945 film San Antonio), "You Never Know Where You're Going Till You Get There" (from the 1946 Joan Leslie film Cinderella Jones), "Carissima" (the song the soprano tabby sings, originally introduced in the 1930 Vitaphone short What a Life), "Frat" (written by John F. Barth, original artist unknown, Sylvester's one-man band tune), and finally "Angel in Disguise" (initially sung in the 1940 film It All Came True).
- Weird Moon: Appears to take place on some alternate Earth where the moon is much, much closer.
- Winged Soul Flies Off at Death: Elmer finds himself ascending to heaven, after he sets off the dynamite. He is briefly relieved, until he sees all nine of Sylvester's lives ascending with him, all singing.
- Team Rocket Wins: This is one of the few shorts where Sylvester actually wins in the end. Although, at the cost of his own life.