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Nightmare Fuel: Brave
The way Bear!Elinor's eyes change from human to feral... *shudder*
The first time it happened, it was a Mood Whiplash, because it switched from a funny/heartwarming scene where Elinor and Merida catch fish together to Elinor almost mauling Merida.
Most of the movie from Bear!Elinor's perspective. You can clearly see how terrified she is about the transformation, and simply struggles with walking normally.
The giganticbear, Mor'du. in the trailer, with its glowing yellow eyes.
And then you see the actual Mor'du. They toned him down a lot for the trailer. Let's see. Instead of glowing yellow eyes, we have a glowing red eye. He's got a huge hump of scar tissue from which protrudes arrows, knives, and even swords, trophies from those that tried to kill him and failed. Even his fur is scarier, going from long and flowing to chopped up. The worst part is that the trailer implies that Merida will shoot him. In the film, all her arrows do is lure him towards her without any noticeable hesitation at all. The only thing that hurts this monster at all is Bear!Elinor, and even then she had to drop a multi-ton rock on him to end him.
Mor'du's actual introduction in the prologue of the film also counts. It starts off with a very young Merida and her family having a relaxing, happy picnic, then a Mood Whiplash in Mor'du's appearance. However, what makes it worse is that the audience knows just a few minutes earlier that Mor'du was watching Merida when she walked into the forest, based on a musical cue alone. What could have happened had Merida notfollowed the wisps back to safety?
Scenes include Wisps luring Merida into the dark forest, Merida exploring some creepy old ruins including a broken tomb and bones covering the floor, and trying to escape an angry Mor'du.
The scene in the abandoned castle. It plays out like a scene out of a horror movie. Merida comes to a horrible realization from a stone engraving with one part sliced out of it that splits one person out of the picture (there's a brief horrifying glimpse of the person chopping at the engraving with an axe and he has the head of Mor'du) that the prince from the legend is Mor'du and then we seeMor'du appearing behind Merida.
And during this scene, you start to notice bones scattered throughout the area. Bones from his previous kills, human included.
Whenever Elinor lapsed into acting like a real bear. It's almost as scary as Merida's interactions with Mor'Du because it's Merida's mother and she literally cannot stop herself because the spell makes the animalistic behavior come and go at random times. Extra Fridge Horror arises when you realize that Merida loves her mother so much that she stayed with her all that time knowing that at any moment, her mother could switch into a normal bear and eat her alive.
The moment where Elinor accidentally catches Merida with her claws, you can just see the horror as she realizes what she's done, even as Merida is frantically trying to cover the scratches and insists it's nothing. (In retrospect, that sounds horribly like a fully-human parent realizing they've become abusive.) Especially when she discovers that she's also hurt Fergus.
Near the climax, the scene where her father locks her in the room while he goes after Bear!Elinor is horrifying for several reasons. For one, her father thinks that the bear killed his wife, so he's out to avenge her two, said bear is his wife, and he comes this close to killing her and three Merida knows that all of this is her fault. Brr.
Mor'du roaring down right on Merida in the climax. Just imagine it. Nearly a ton of killing machine towering over you, roaring barely inches from your face, its roar shaking your very core and bones and will likely kill you and devour you and there's nothing you can do about it. Absolutely nothing except scream.
..for your mom who is now a bear of comparable size to Mor'du who proceeds to throw off 4 clans worth of fully-grown Scottish warriors to literally beat the immortality out of him.
Finding out the true nature of Mor'du is pretty horrific on its own when you think about it. The prince is implied to have turned into an animal right there in the throne room and killed everyone, including his family, and he was powerless to stop it. And then it's heavily implied that its either his spirit or the souls of his familiy manifesting as the Wisps is so he can finally be put out of his misery and killed so he can finally reunite with them, essentially meaning that he pulled a Suicide by Cop. In a kid's movie.
Even worse: Even if Mor'du understood the real meaning of the Curse Escape Clause (and given the number of claw marks on his part of the stone it's quite possible) he was stuck as a bear forever because whether he intended it or not he killed everyone he could've apologized to.
What's especially worse is we actually get to learn about Mor'du's backstory in the new short that appears as a Bonus Feature on the Blu-ray/DVD. The Witch, who is narrating the story, tells us that after Mor'du transformed into a bear, to quote the witch, instead of choosing to mend the bond torn by pride, "he instantlyacceptedhis new form" and then killed his brothers. *shudder*
A bit of Adult Fear near the climax where Fergus finds Elinor's room trashed and her clothing torn, coming to the somewhat-true realization that a bear was in there. Then he finds what was likely the same bear attacking his daughter.
Poor guy gets another one at the beginning of the film. Imagine having a little picnic with your wife and small daughter. You get the scene right out of a post card where mom is holding your darling little girl. Then bear, going after your wife and kid.
The song "Mor'du, Mor'du, Mor'du" — funny song sung by outrageous Scottish king to entertain his friends, right? Now go back and re-listen, knowing that his wife Elinor turned into a bear & was mistaken for Mor'du, so everything he was singing about, he intended to fully do to his wife once he caught her. Pleasant dreams.
The scene where the men chase Bear!Elinor through the forest, catch her, and restrain her so that she's helpless to fight back.