18. Treehouse of Horror 11
Treehouse of Horror 11 makes such a solid start that you'd be forgiven for expecting it to be much higher on this list. Unfortunately, the fantastic 7 minutes of G-g-g-host D-d-d-ad (a top 10 story, in my opinion) is quickly supplanted by a lazy fairytale parody that offers nothing in the way of particularly amusing material. Adding on to that, Night of the Dolphin just meanders along and is all too predictable. It's still not bad, per se, but there are plenty of Treehouse of Horror episodes you should watch before this one.
17. Treehouse of Horror 20
This episode kicks off with a critique on the modernisation of Halloween costumes. It's fitting, then, that this episode spotlights a triumvirate of traditional tales: Hitchcock – an influence the show loves to mine – musicals and, *sigh* zombies again. If you thought that well ran dry a decade prior then, boy, have I got news for you. For a big anniversary, this episode feels fairly standard – but Moe's deliberately terrible song and dance numbers bring the pizazz and cap off a nice episode.
16. Treehouse of Horror 24
Guillermo del Toro's couch gag and the Dr Seuss tribute are overflowing with such joyous creativity that it's a real kick in the teeth that the rest of the episode doesn't live up to the ridiculously high benchmark of the opening 10 minutes. Dead and Shoulders's concept has been done far better in the show's cousin Futurama and, ironically, isn't given room to breathe because of the clipped runtime. The circus segment is a series of one-shot jokes and visual gags that don't quite knit together the threadbare plot it comes with. Still, this is a real animation tour-de-force, and well worth a watch.
15. Treehouse of Horror 13
Number 13: Unlucky for some, but the thirteenth Treehouse of Horror shows that some of the magic was still there. Send in the Clones in an inspired story and – as we near #1 – the trend of entertaining characters carrying stories rather than vice-versa becomes readily apparent. The imagery of the Island of Dr Hibbert is also very strong, but the second story not only glamorises gun violence, it also steals a premise from eleven years earlier. Two out of three ain't bad, though.
14. Treehouse of Horror 25
Fittingly for such a big milestone, the 25th Treehouse of Horror works as a fine-tuned microcosm for the changing face of the Simpsons' Halloween anthology. Parodies, again, are the name of the game and A Clockwork Yellow is one of their better efforts. Bart going to Hell, surprisingly, took this long – and it doesn't disappoint, with gruesome gags aplenty. The Others is also a neat, knowing nod for classic fans, which is nice. A terrific effort all round.
13. Treehouse of Horror 8
Following on from such a brilliant run of Treehouse of Horror episodes in the mid-to-late '90s, 8 feels like a slight letdown, but it's not without its moments. Homer – at his most obtuse – carries The Homega Man's paper-thin premise. He also gets the best moments in Fly vs. Fly and Easy Bake Coven, but the former lacks Jeff Goldblum and the latter feels like, for better or worse, a more restrained Halloween effort after previous years shambled onto the scene. A solid effort, if not a great one from The Simpsons' Golden Age.
12. Treehouse of Horror 3
Probably the most disappointing of the early Treehouse of Horrors, though an average season 4 Simpsons episode is still better than most shows ever produced. King Homer may be beautifully animated, but it rarely strays from full-on parody, and while Clown Without Pity features one of the show's most unsettling images in a knife-wielding Krusty the Clown doll, it doesn't really bring the laughs (cursed frogurt aside). The final segment, Dial Z for Zombies bring you guessed it, zombies into the Treehouse of Horror fore. Except the shambling undead will be covered in far funnier and fateful Treehouse of Horrors further down the line.
11. Treehouse of Horror 12
Season 13 really marked the point where the show reached such a downturn that it was seen as the end of many fans' love affair with the longest-running animated show in history. Treehouse of Horror 12, though, is a strong start to the season. Gypsies curses, Pierce Brosnan playing a knockoff HAL, and a half-baked Harry Potter parody (saved by the serpentine Smithers) all come together to form an episode that is a bit all over the place thematically, but still proved the writers weren't (and, frankly, still aren't) as creatively bankrupt as many would have you believe.
10. Treehouse of Horror 14
A kinda meh Frink story aside, this is a great collection, and well worthy of a spot in the top 10. Homer taking up the mantle of the Grim Reaper, and trying to fool God, is hilarious as it is dark. Milhouse and Bart getting a watch that stops time is perhaps the least scary Halloween story to date up to this point, but it still makes for a genuinely intriguing plot based around the subservient blue-haired best friend of Bart. Fun fact: This is also the first Treehouse of Horror to use a 'Treehouse of Horror' title card in the actual episode – and it's painted with Homer's blood.
9. Treehouse of Horror 18
Treehouse of Horror 18 is a love letter to the show's past. Not only is it a fitting tribute to The Simpsons Halloween canon, with neat spins on well-established narratives, it has some fantastic references for long-time fans of the show, too. The Kodos/Homer shower scene is awkward as hell and you'll be laughing throughout, Mr and Mrs Simpson is a parody that lets the action and Marge's chemistry with Homer do the talking, and Heck House is joyfully anarchic, finally shining a spooky light on Springfield's kids. Don't let the season fool you, this is just as good as the classics.