With Catlike Tread! *STOMP* Upon our prey we steal! *STOMP*Explanation The "sneaking about while making a lot of noise or talking about how stealthy they are being (or both)" is widely used in crime-caper and spy-thriller parodies. Admittedly, most uses don't involve singing. The melody itself has also become a memetic mutation, spawning first "Hail, Hail, the Gang's All Here" which in turn mutated to the Black Comedy variant "Hail, Hail the Gangrene's Here".
"Well, hardly ever!"
The Memetic Mutation on this one was so big back in Gilbert and Sullivan's day that Gilbert remarked he never wanted to hear it quoted again. "What, never?" some nearby wag remarked. The writer was unable to stop himself from responding in kind.
The ending of The Pirates of Penzance originally had, after the revelation that the pirates were noblemen gone wrong, a variation on this exchange: "What, all noblemen?" (etc.)
Shows up in satires, for self-deprecation, or to question the truth of a negative statement ("I don't...", "They won't...", "He'll never...", "She didn't...". Often shortened to "'<Negative statement>', 'What never?', 'Well, hardly ever.'" or "<Negative statement>, well, hardly ever."
"To be or not to be?": Parodied, punned on, and played with innumerable times. Also used seriously in fiction to indicate that a character is suicidal. Explanation From Act 3, Scene 1
"Whether it is nobler in the mind to suffer the slings and arrows of outrageous fortune..." Explanation From the same speech, wondering if he should survive the anguish he's going through.
"To sleep: perchance to dream..." Explanation From the same speech, wondering if there will be peace after death.
"Though this be madness, yet there's method in't." In its most common modern mutation, turned into "There's method to my madness."
"Murder most foul..." Explanation From Act 1, Scene 5: When the ghost Hamlet sees explains why he exists, claiming he was murdered. Used for the title of an Agatha Christie murder mystery, at least one non-fiction true-crime book, a game, and used surprisingly often in articles about real life murders.
"Alas, Poor Yorick. I knew him, Horatio." Both the speech itself and the visual of a guy talking to a skull have mutated. (And the line is often misquoted as "Alas, poor Yorick, I knew him well.")
"The play's the thing" Explanation From Act 2, Scene 2: Hamlet uses the play as a plan for his uncle's conscience to admit the crime of murdering Hamlet's father. Some playwrights used to believe that their work would cause the audience to have better moral values.
"Double, double, toil and trouble. Fire, burn and cauldron, bubble. Eye of newt and toe of frog, wool of bat and tongue of dog." Explanation From Act 4, Scene 1: This scene has long served as the basis for a common presentation of witches in general, stooping over a steaming cauldron. It's also a likely source of "eye of newt" as a standard ingredient in witches' brews, magic potions, and spells in general.
Out, Damned Spot!! Explanation From Act 5, Scene 1: Lady Macbeth shouts this while sleepwalking, trying to wash her hands. She still imagines that blood stains are on her hands.
"Romeo, Romeo... wherefore art thou Romeo?": Mutated into being understood as "where are you, Romeo?" rather than the real meaning, "why did you have to be Romeo (Montague)?"
What's in a name? That which we call a rose by any other name would smell as sweet. Explanation From Act 2, Scene 2: Juilet believes that a name is a meaningless convention and that she only loves Romeo, not the Montague name.
"A plague on both your houses!" Explanation From Act 3, Scene 1: Mercutio shouts this as he wishes illwill toward the Capulet and Montague families for Tybalt stabbing Mercutio.
Two households, both alike in dignity... Explanation The first line of the prologue, introducing the feuding families.
Star-Crossed Lovers. Explanation The sixth line of the prologue, which means that Romeo and Juilet are destined for tragedy.
The Analogy Backfire of describing a relationship as "like Romeo and Juliet". What, you're both going to kill yourselves in the end?
The cimematography is widely copied and parodied, the most common forms are "person spinning joyously in a meadow sings about something stupid or depressing"; "person spinning joyously in a meadow has something bad happen to them"; and simply "Person spinning joyously in meadow singing (badly)". Another common parody is to overlay the soundtrack of birds and music with unpleasant noises.
The phrase has also become a memetic mutation, crossing over into Horror fandom, where it is used to herald something bad about to happen.
According to No Exit, "Hell is other people." It is most commonly mutated into either "Hell is X" or "X is other people".
She Stoops To Conquer: "Ask me no questions, and I'll tell you no fibs."Explanation From Act III
Little Shop of Horrors: "FEED MEEEEEE, SEYMOUR." Explanation Said by Audrey the Plant when it wants to eat more meat.
It's becoming increasingly common on MLIA to write a comment actually related to the post, then, at the end of the comment, begin singing a Wicked-song.
"The Time Warp" from The Rocky Horror Picture Show: used when things are getting weird, possibly also part of the inspiration for the Peter Panda Dance in the movie The Pacifier.
"We love you Conrad, oh, yes we do-ooooo!" from Bye Bye Birdie. a common mutation is simply appending "Oh, yes, we do-ooooo!" to the end of a statement.
A very old meme comes from Johann Wolfgang von Goethe's play Götz von Berlichingen, in which the title character's castle is under attack in the third act and a bishop demands his surrender. Götz responds with "Leck mich im Arsch," which translates to, essentially, "kiss my ass." Almost immediately after the play's debut, it became the most famous quote from the play, to the point where "to quote Götz von Berlichingen" is a common German euphemism. Mozart even wrote a song that consists almost entirely of quoting it.
Peer Gynt: To be "utterly yourself"/Sig selv nok. Entered Norwegian political debate decades ago. The play will never stop mutating.
The King and I gives us memes, tropes, et cetera, et cetera, et cetera.
Sweeney Todd: The Demon Barber of Fleet Street: "AAAT LAAAAAAAAAAAAAAST! MY AAARRRMM IS COMPLEEEEETE AGAAAAAAAAAAAAAIN!!!" This troper defies any two Sweeney fans to get together and discuss the musical without at least one of them parodying that. In all probability, both will in sycronisation.
The Vagabond King: "And to Hell with Burgundy!" Explanation Originally the final line of the rousing "Song of the Vagabonds," wildly divorced from its original context by haters of fine wines, e.g. Peter in The Goon Show: "I like claret, and to hell with Burgundy!"