The scene where Scrooge enters his lonely mansion late at night. He sees the ghost face of his former partner Jacob Marley on his door, then a ghostly hearse riding up the stairs. Later he goes to his room but still can't forget the image he saw earlier. Then the bell in his room starts ringing on its own and Scrooge hears chains rattling from beneath the cellar and slowly coming towards him. Then Marley's ghost flies through the door.
When Scrooge mocks Marley the ghost flies into a rage and his jaw falls open unto his chest.
This part especially is something that few people know these days, the cloth tied around Marley's head and his jaw opening creepily wide is because the ligaments in the jaw are among the first part of the human body to decay after death, resulting in the unsettling "screaming corpse" effect. To prevent this, before embalming was developed, people were buried with their jaws held closed with cloth ties. So yeah, Marley isnt just a ghost, he's a rotting corpse of a ghost too.
Marley's fate in general. He warns Scrooge how he is doomed forever and carries a chain with the weight of his crimes. When Scrooge sees him disappear through the window the night sky is filled with ghosts of former colleagues of Scrooge, all doomed to wander around with chains and weights. One of them tries to help a poor woman crying over her child, but since he's doomed he can no longer do anything for her.
The second paragraph describing the Ghost of Christmas Past makes it sound like some kind of Eldritch Abomination. No wonder most adaptations don't bother trying to match it on screen.
"... its belt sparkled and glittered now in one part and now in another, and what was light one instant, at another time was dark, so the figure itself fluctuated in its distinctness: being now a thing with one arm, now with one leg, now with twenty legs, now a pair of legs without a head, now a head without a body: of which dissolving parts, no outline would be visible in the dense gloom wherein they melted away. And in the very wonder of this, it would be itself again; distinct and clear as ever."
The Ghost of Christmas Present showing Scrooge the children Want and Ignorance from under his robe. These starved and bony children even frighten Scrooge.
The Ghost of Christmas Yet To Come is a towering, wraith-like figure in a dark hood whose face is never seen, and who never utters a word, simply pointing and letting Scrooge's Bad Future speak for itself.