Itchy and Scratchy
===============================================================================
Itchy is the mouse.  Scratchy is the cat.
"They hate each other and they're not afraid to show it."
===============================================================================
A list of cartoons
===============================================================================
???? - Let Them Eat Scratchy

???? - (untitled) Itchy rolls Scratchy's severed head out of his mouse hole

7G04 - (title?)

7G12 - Burning Love

7F03 - (title?)

7F04 - title sequence only (on the alien spaceship's TV screen)

7F09 - Hold That Feline (I kicks S an exploding football)
     - Kitchen Cut-Ups (I tries to stab S with a knife)
     - Messenger of Death (I blows S's head off with a bazooka)
     - (untitled) (I bops S's eyes out)
     - (untitled) (I and S attack a Marge look-alike)
     - (untitled) (I blows up S with TNT)
     - Porch Pals (I and S drink lemonade) (reprised briefly in 7F13)
     - (untitled) (I and S pull larger and larger guns on each other)

7F13 - Porch Pals (audio only; see 7F09)

7F16 - Sundae, Bloody Sundae
===============================================================================
Lyrics
===============================================================================
  They fight!
  They fight!
  They fight and fight and fight!
  They fight fight fight!
  Fight Fight Fight!
  The Itchy and Scratchy Show!

On Itchy and Scratchy and Marge, Mark A. Holtz reports that the lyrics were

  They love, they share,
  They love and share and care,
  Love and share!
  Share and care!
  The Itchy and Scratchy show!

Some others think it was

  They love
  And share.
  They love and share and love.
  They love love love.
  Share share share.
  The Itchy and Scratchy show.

Anybody know for sure?