The Demon Barbers need to find out about a song by John Forster on his "Helium" album where he uses the "Barber of Seville" music and uses references to all the demon barbers (including Sweeny Todd) in the lyrics. The people who get knocked off are legion (and useless!)
The sound effects on the track (guns, incoming shells, machine guns, explosions, as well as the "zeet! zeet! zeet! zeet!" violins from "Psycho" are also hillarious.

His web site is at http://www.johnforster.com/

Figaro Todd

This is the tale of a barber,
This barber was rather odd.
His Christian name was Figaro.
His family name was Todd.
He serviced his regular clients
With true dispatch and skill.
This is the tale of Figaro Todd,
The Demon Barber of Seville.
Count Almaviva had no life.
He tried to boink the barber's wife.
So when 'twas time to trim his mop
Figaro took a whole lot of the top.

Then Cherubino, horny youth,
Called Figaro to pull his tooth.
But Todd got in a jealous huff
And pulled a bunch of unrelated stuff.

Figaro clip, Figaro snip.
Figaro slice, Figaro dice.
Figaro chop, Figaro lop.
Figaro hack, Figaro whack,
Just unbridle all that homocidal rage.

A couple blocks from Figgie's shop
Lived Don Giovanni, famous fop.
The cad came in with two days' beard.
When Todd was done two weeks worth disappeared.

Outside a bullring down the road
Carmen caught a dasty code.
She called for leeching, which was dumb. [Figaro!]
He leeched the mezzo straight to kingdom come.

With every slash, every cut, [Figaro!]
He was getting revenge, revenge for what? [Figaro!]
Maybe a snub deep in his past. [Figaro!]
Maybe they always chose him last. [Ahhhhh!]
Nobody knew, hadn't a clue.
It's simply what Demon Barbers do.

They clip and they rip
And they slash and they bash
They sever and shatter and batter and mangle and maim.

Don Miguel, the Demon Barber of Castile,
Heard of Figaro's success and couldn't deal.
He packed his razors, shouting "Vengeance will be mine."
But by now, Todd had set off on a journey down the Rhein.

Those Rheinmaids' singing made him sick.
A depth charge shut them up real quick.
Then the high point of the week--
Eight Valkyries mit plastique.

The barber switched on A&E
And saw Three Tenors, count 'em, Three.
He did his thing and when 'twas done
He'd reduced the tenor count to less than one.

John Denver caught the barber's eye.
(Heave your cleaver high, Figgie.)
He lowered his Rocky Mountain High.
(Yanni, too, must die, Figgie.)
And Yanni at the Acropolis
(Phony phony man.)
Another one whose work we'd never miss.

Figaro biff! Figaro boom! George Winston!
Figaro bang! Figaro zoom! Zamfir!
Figaro wham! Figaro blam! Kenny G!
Figaro klonk! Figaro bonk! Michael Bolton!

Figaro mutilate, Figaro lacerate,
Figaro sever and mangle and maim.
Figaro, oh what a wonderful game,
Oh, what a wonderful wonderful game.

Figaro whack 'em and Figaro hack 'em and
Figaro stack 'em and Figaro
Slit 'em and split 'em and pit 'em and hit 'em and
Slit 'em and split 'em and pit 'em and hit 'em again.

Stab 'em and slab 'em and
Maul 'em and haul 'em and
Claw 'em and saw 'em and
Snip 'em and
Clip 'em and grip 'em and rip 'em and whip 'em and
Sever and shatter and batter and mangle and maim.

Puncture rupture sunder and kill,
Demon Barber (incoming shell sound)
Barber of Seville.

Hatcheta hatcheta hatcheta hatcheta hatcheta
Butchery butchery butchery butchery
Barber of Seville.