The Itchy & Scratchy Show is a show within a show in the animated television series The Simpsons. It usually appears as a part of The Krusty the Clown Show, watched regularly by Bart and Lisa Simpson.
Itself an animated cartoon, The Itchy & Scratchy Show depicts an anthropomorphic blue mouse, Itchy (voiced by Dan Castellaneta), who repeatedly kills an anthropomorphic black cat, Scratchy (voiced by Harry Shearer) in violent and nasty ways.
The pair typically appear in the form of 15-60 second cartoons that are filled with decidedly gratuitous over-the-top violence, usually initiated by Itchy the mouse against Scratchy the cat; although smaller, Itchy is almost always the victor.
The Itchy & Scratchy Show is essentially a parody of traditional cartoons or take-offs on famous films, but the plot and content are always ultra-violent and frequently cruel and gory. The most direct and obvious influence is Tom and Jerry, the classic animated series which was also about a constant battle between a cat and a mouse, with the mouse usually victorious.
There was no blood or gore in Tom and Jerry and yet it still caused debates about TV violence when these cinema cartoons were syndicated. Itchy & Scratchy deliberately upped the ante yet showed Lisa and Bart Simpson understand that animated cartoon violence is nothing like real life and is frequently hilarious.