World War II, also known as "The Cat Next Door", is an unseen cat character in the Peanuts comic strip by Charles M. Schulz. World War II is an extremely vicious cat who terrorizes Snoopy and Woodstock. Whenever Snoopy mocks the cat from across the yard, the cat slashes Snoopy's doghouse or sometimes, him. Charlie Brown usually ends up having to buy another doghouse, as a result.
Occassionlly, Snoopy will attack the cat "off-stage" if someone (such as Woodstock) is in mortal danger. However, Snoopy's attacks usually result in him looking beaten up or scratched when he reappears.
World War II's paw has been shown briefly in The Charlie Brown and Snoopy Show, in the short "Blanket" (in which Snoopy and Linus van Pelt try to retrieve Linus' security blanket from next door after Sally Brown's friend Eudora gives it away to the cat) from the first season episode "Snoopy's Cat Fight" and in the short "Snoopy's Foot" from the second season episode "Snoopy and the Giant". His paw appears as orange in "Snoopy's Foot" but is white in "Blanket". Of course, it is possible for one cat to have paws of different colors.