Itchy is the cartoon mouse from Itchy & Scratchy. He is a serial killer whose favorite victim is Scratchy. He almost always succeeds in killing Scratchy. There is only one known episode where Scratchy defeats him.
Itchy first appeared in "Itchy the Lucky Mouse in Manhattan Madness", in which only Itchy appears, without Scratchy, and Itchy kills an Irish man and Teddy Roosevelt. This was the very first of many episodes where he would appear.
His ears resemble Mickey Mouse's, his name is like Oswald the Lucky Rabbit's and he plays the role of Jerry from Tom and Jerry. In a parody of the view of Jerry as a villain, Itchy is depicted as a serial killer torturing and killing the innocent Scratchy, contrasting Jerry's mutual slapstick relationship with Tom (in most episodes Tom is pranked by Jerry only because he attacked Jerry in the first place).
The Itchy & Scratchy Land is an Itchy and Scratchy theme park. It has parades with robots resembling Itchy and Scratchy which are supposed to be inoffensive and only attack themselves. While on vacation, the Simpsons were attacked by a group of robots, until they used the cameras flashes to short circuit them (the reason flash snaps are not allowed).
Itchy and Scratchy also appear in The Simpsons Movie, in a short film that the Simpsons are watching in the movie theater before the actual movie begins. He kills Scratchy by filling a bunch of rockets in his mouth and then explodes him to pieces.
- For a full list of both Itchy and Scratchy appearances, please see The Itchy & Scratchy Show