This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Hoodwinked
When Boingo snaps. He's laughing amicably and then it just turns into a mad laugh.
The speed and pitch of the chimes on the roof of Kirk's schnitzel truck. Based on the sound, are apparently tied in to the driving speed of the vehicle, much like an old-fashioned siren... as we discover after Vincent and Lisa steal it and drive it very slowly up the mountain. Compare it to the noise the chimes make during the "Schnitzel Song" when they're working at regular speed. It sounds creepy when it's wound down.
Then again, they had outfitted it with tank treads to suit it for off-road and alpine terrain (almost like a snowcat conversion). It was going to drive slower no matter what.
The mine carts take on two levels of this - one from "Be Prepared" and another from the Wolf's story. They're gravity powered, and apparently they even ride around driverless with dynamite stored in the back, and matches. And that dynamite is loose, and if someone should so much as mistake it for a box of candles, you can end up blowing up a trestle easily.
In Red's story: the lighting when she falls from the cable car. There is very little sunlight, only a few beams getting through the trees. And the Wolf shows up out of nowhere. And the Wolf-Away part of the encounter gives a jump scare.
Sure, Wolf is actually a good guy, but Red didn't know that at the time. Nor did we, of course.
When Red falls from the cable-car. Watch and Boingo doesn't quite reach for her, as much as for the basket. And when she falls, he's not looking scared. The look on his face is actually furious. Instantly something seems very wrong. It only makes sense in the third act.
That entire mine cart section of "Be Prepared" is an In-Universe one for Red. She has the appropriate reaction that a normal person should have, while you're paying more attention to Japeth's song.
How Boingo intends to get rid of Red: sending her down in a cable car stuffed with dynamite, Bound and Gagged. Yes she gets out but what a way to die...