In the cartoon “SpongeBob SquarePants”, Mr Krabs, purveyor of krabby patty hamburgers, is a frequent and ruthless price-gouger. He can get away with it because he has no competition, save for the unappetising Chum Bucket. McDonald’s, a chain that flips real-world hamburgers, can only dream of Mr Krabs’s pricing power. It has been forced into a fast-food price war.