Powers of Ten parody

The Powers of Ten parody is a couch gag which has been used in three episodes.

Plot
The Simpsons sit down on the couch as normal when suddenly the usual view of the couch is replaced by an overhead shot of the house. The point of view moves further and further away as we see an overhead shot of the neighborhood, an overhead shot of the United States, an overhead shot of the North American continent and the Western Hemisphere, an overhead shot of the Earth, the solar system, and Kang and Kodos floating in space next to their broken spaceship. Soon, many stars fill the screen as they form into the Milky Way. Other galaxies form and turn into atoms, which turn into simple molecular structures, which turn into more complex molecular structures, which turn into DNA helices, which pan out into a blank yellow expanse, which is revealed to be Homer’s bald head. Finally, the view returns to the couch scene. Homer stares blankly for a moment, then utters, "Wow..."

Re-uses / Variants
The gag has been used in two other episodes:
 * In "On a Clear Day I Can't See My Sister", Kang and Kodos are laughing as they appear in the point of view. At the end, Homer says "Cool" instead of "Wow".
 * In "Eternal Moonshine of the Simpson Mind", Homer says "Weird" at the end.

Behind the Laughter

 * The gag is a parody of the 1977 science short film .
 * The music playing is , most famous for its use in the film 2001: A Space Odyssey.