Gravity Falls

Two animated children and a small pig ride a vehicle through a dark, fiery landscape, their expressions shifting to fear as they encounter a large, shadowy figure with glowing red outlines. The scene cuts to a man in a suit confronting a skeletal figure in a red-lit room, then returns to the children and the man, now together in a dark space, as text appears around them, culminating in a shot of a skeletal creature in a dark, watery environment.