Ep 6. Treehouse of Horror XVIII

In the fantastic frightology that is Treehouse XVIII, an unwelcome alien crashes with the Simpsons in "E.T. Go Home"--and turns out to be a precursor to an invasion from space, Homer and Marge are paid assassins who nearly kill each other in "Mr. And Mrs. Simpson", but then find their marital spark has been restored, and Ned Flanders tries to frighten the fun out of Halloween in "Heck House"--when the kids laugh at his efforts, he teaches them what true terror is.