The politically-themed “Citizen Kang” installment from “Treehouse of Horror VII.” (Fox)

Since 1990, we’ve been treated to an annual half-hour of of horrifying tales from the town of Springfield, riffs on everything from “The Shining” (see Season 6’s “The Shinning”) to “The Twilight Zone” (“Terror at 5 1 / 2 Feet” from Season 5, among several others) to, inevitably, “It’s the Great Pumpkin” (Season 20’s “It’s the Grand Pumpkin, Milhouse”).

On Sunday at 8 p.m., “The Simpsons” brings us “Treehouse of Horror XXII,” which includes spoofs of “Avatar” and Showtime’s “Dexter.” The serial killer in the latter? Ned Flanders. Obviously. (Watch a preview below.)

Before you experience this season’s satirical scares — which, thanks to World Series scheduling, actually airs before Halloween this year — peruse this list of the most significant “Treehouse of Horror” installments from years past. What does “most significant” mean? That these are the six vignettes that were the most groundbreaking, daring and/or memorable from the annual “Treehouse” trilogies of terror. Not the funniest or even my favorites, necessarily. But the most significant. (And yes, these are weighted toward earlier seasons. Why? Because “The Simpsons” tended to be more “significant” then.)

Disagree and think I should have included some others on this list? Weigh in by posting a comment.

6. “Citizen Kang” (Treehouse of Horror VII, Season 8)

“The Simpsons” has never shied away from political mockery. But in the third installment of the 1996 “Treehouse” episode — which aired a little over a week before the presidential election — the writers took things to a newly audacious level by having the resident “Simpsons” extraterrestrials, Kang and Kodos, kidnap candidates Bob Dole and Bill Clinton, assume their identities and continue their campaign efforts. For those who have always suspected politicians were from another planet, this provided cartoon-comedy proof.

5. “Hungry Are the Damned” (The original “Treehouse of Horror,” Season 2)

This parody of the “Twilight Zone” episode “To Serve Man” is significant primarily because it introduced us to the aforementioned Kang and Kodos, who have appeared in all the Halloween episodes that followed. In fact, they are to “Threehouse of Horror” what Alfred Hitchcock cameos were the to the master of suspense’s films.

4. “The Devil and Homer Simpson” (“Treehouse of Horror IV,” Season 5)

The opening story in this episode, co-written by Conan O'Brien, may not have a been a game-changer. But I would argue it’s the most memorable and most-often quoted (“Mmm . . . forbidden doughnut
) of the “Treehouse” bits, as it features the delicious premise of Homer making a deal with the devil over a doughnut and suffering Dante-esque punishment in Hell. Well, what’s supposed to be punishment. When Satan’s minions force-feed Homer a never-ending supply of sugary breakfast treats, is it any surprise that he continues to binge while showing no sign of disgust?

3. “The Raven” (The original “Treehouse of Horror,” Season 2)

This moment — when James Earl Jones read Edgar Allan Poe’s sad, disturbing poem in its entirety while Homer and Bart acted out its narrative — established that “The Simpsons” was not just some lowbrow animated sitcom about a kid who said, “Eat my shorts.” It was intelligent, literate and willing to experiment with its format — at Halloween and, as we’d continue to learn, any time of the year.

2. “The Shinning”(“Treehouse of Horror V,” Season 6)

On several occasions in “Treehouse of Horror” history, the episodes have been grisly and genuinely frightening. But perhaps the scariest imagery of all was the sight of Homer going Jack Nicholson-style psycho on his family after bring deprived of beer and television.

1. “Homer³” (“Treehouse of Horror VI,” Season 7)

A true watershed moments for “The Simpsons” and one that, with its 3-D animation, seems particularly prescient in today’s multi-dimensional entertainment world. But the real kick in the pants, aside from the hilarious reference to “Tron”? The conclusion, in which we see Homer Simpson in a live-action setting for the first time.