Oh the shark has pretty teeth dear
And he shows them pearly white
Just a jack-knife has Mac-heath dear
And he keeps it out of sight
Even sharks are more honest than Macheath, sayeth Bertolt Brecht.
Macheath is the villainous protagonist at the center of Kurt Weill and Bertolt Brecht's Die Dreigroschenoper, translated into English as The Threepenny Opera. "Mack the Knife," the name of the murder ballad (moritat) that introduces Macheath into the play, negatively compares the show's anti-hero to a shark.
The shark might be scary, but it approaches you open-mouthed, showing fangs and all. After it kills you, the blood is everywhere. In other words, with a shark, you know your enemy. With Mack the Knife, it's quite the opposite. The man's got the knife drawn to kill you, but you don't see it coming.
In the verse that follows, we also learn that Mack wears gloves to hide the blood (maybe literally, but probably also metaphorically). He's a villain who gets away with it, and his charm and charisma make it all the more insidious. These first two verses can be summed up simply by saying that Macheath, a.k.a. Mack the Knife, is more dangerous than a shark.
When the shark bites with his teeth dear
How does it feel, dear listener, to be referred to as "dear" all the time?
The "dears" were added by Marc Blitzstein in his English translation of the German song.
Adding "dear" the end of lines accounted for the English version coming out with fewer syllables, but they also have a creepy effect. It's strange to be called by an endearing term while you're listening to the story of a serial killer. It definitely fits Mack the Knife's personality—he's cozying up to you even as he's murdering people left and right.
On the sidewalk Sunday morning
Lies a body oozing life
This line manages to be poetic, graphic, and sensational all at the same time.
What does a Sunday morning bring to mind? We thought of churchgoers in their Sunday best, happily catching up with their fellow congregants, of teenagers blissfully sleeping in till all hours of the afternoon, and of thick Sunday papers (or perhaps slim iPad editions) full of comics and crossword puzzles, perhaps enjoyed in a sunny breakfast nook with a cup of hot coffee.
But no. This song gives us a corpse lying in a pool of blood. We probably should have seen that coming.
Louis Miller disappeared dear
After drawing out his cash
And Mac-heath spends like a sailor
One of the tricks up Macheath's sleeve is apparently murdering the rich and making off with their money.
Part of the brilliance and interest of Macheath's character is that, while he is supremely cold-blooded, he's something of a Robin Hood (who was originally an English folklore hero, not a Disney character).
He's down with the poor and destructive to the rich, and no one quite knows how to read him. "What is robbing a bank compared to founding a bank?" he says at some point (great words to charm a few communists, if not to stay on the right side of the law).
Sukey Tawdry, Jenny Diver
Polly Peachum Lucy Brown
O the line forms on the right dear
Now that Mackie's back in town
This little litany of names is actually a list of Macheath's lovers in The Threepenny Opera.
Mack has a way with women, and they line up for the chance to spend time with him.
In the plot of the play, the charms of this corrupt gangster eventually lead him to a pardon from the Queen herself. The moral of the story is sort of an amoral moral: the bad guy gets off easy, but people are happy with that. The play's closing number is "a plea that wrongdoing not be punished harshly."