Alas, Poor Scrappy: Gurgi sacrifices himself to destroy the Cauldron Born Army, but he is resurrected.
Anticlimax Boss: Despite all the build up the character had, the Horned King doesn't put up much of a fight before he is sucked into the cauldron: he lunges unarmed at Taran and grabs him, showing no display of powers or fighting abilities whatsoever, and is killed when Taran pushes him in the general direction of the cauldron.
Counterpart Comparison: With Link. Predating The Legend of Zelda by a year, Taran wears clothes and carries a sword strikingly similar to those of Link in his very early years. Plus looting dungeons, working well with animals, wielding a magic sword, having to stop a very old Big Bad from getting an artifact of great power, and breaking lots of pots. Also, Eilonwy seems to be this to Zelda.
Peter Jackson and Andy Serkis seem to have taken inspiration from Gurgi's voice and mannerisms...
Ensemble Darkhorse: The Horned King. Even if the movie failed at the box office and is one of the lesser known Disney feature films, The Horned King is a cult favorite within the Disney fandom and many times is compared with the likes of Maleficent and Chernabog. He probably would've had a respectable presence in Disney properties if it hadn't been for the movie's poor initial reception. Fans have even demanded Disney to let the Horned King to make an appearance in future Kingdom Hearts games. Being played by John Hurt probably has quite a bit to do with it.
And Japanese Love the Horned King: Popular enough to appear in several video games as the Final Boss and to be the center of the Cinderella Castle Mystery Tour at Tokyo Disneyland. Heck, if anything, he's a constant throw in for a possible Kingdom Hearts villain for what it's worth.
"I know! Let's make a movie about an evil cauldron that raises invincible undead armies, and can only be stopped by somebody committing suicide inside it! Do you think we'll have any trouble getting a G rating?"
Never Live It Down: The troubled production and ultimate box office failure of the film shook the Walt Disney Company so much that even after the successful revitalization of its animation department in the years that followed, they largely ignored it for the next decade or so and have released virtually no merchandise tied to it; not even of Princess Eilonwy who remains absent from the Disney Princess lineup. It eventually received a full VHS release and later a DVD release thanks to its respectably cult following, but remains one of its least-publicized pictures.
Nightmare Retardant: The Horned King's theme music is frightening—until that theremin kicks in and makes the sound of a B-movie slide whistle.
Same with Taran and three-dimensional Disney characters; he has a very flawed personality, but because of that, a very human one.
Quality by Popular Vote: It could be argued that the film has suffered from this. Because it was unpopular in the theaters, it's been severely underrated. Although there is good reason it was unpopular in theaters. Many, if not all, characters in the movie are considered to be the Scrappies of the Disney Universe, with Gurgi and Creeper being the most universal. It doesn't help that the plotting and pacing of the movie is quite inconsistent and it seems to lack a proper theme.
Gurgi isn't quite as bad as most examples, but he has the makings of one: a small, nonhumancomic relief character with a grating voice whom the filmmakers are desperate to prove is cuter and more charming than he is.
Creeper may also qualify, given his tendency to break the mood during some of the Horned King's more genuinely frightening scenes.
Squick: Orwen's unsettling attraction to Fflewddur.
They Wasted a Perfectly Good Character: The Horned King is held by some to be a genuinely terrifying Disney villain, yet sadly has little to show for this due to his surprisingly easy defeat at Taran's hands.
True Neutral: The three witches. They're more concerned with serving their own goals than getting involved in the war between good and evil happening just outside their swamp. It's possible that this is the very reason they were appointed to guard the Black Cauldron in the first place—they have no interest in using it, only having it, and it's apparently completely safe from the Horned King so long as it's theirs. The only nasty thing they do is transform people into frogs and eat them, but judging by their actions, it's possible they only do that to intruders.
Vindicated by History: It's noticeably darker tone, new animation format, Executive Meddling and a lot of bad luck made 1985 viewers see the film as a train wreck; modern viewers can appreciate it more.
Visual Effects of Awesome: For all its problems, the film's animation stands out as one of its more polished elements and really lends itself on the dark tone and atmosphere of the story.