When he turned around there was a moose by him and he had attacked him while he's in the water, and so he thought he would die.
Answer:
Scrooge believes Marley's ghost is the result of an indigestion. He says "You may be an undigested bit of beef, a blot of mustard, a crumb of cheese, a fragment of an underdone potato. There's more of gravy than of grave about you, whatever you are!".
