Deliberate exaggeration, which no one takes literally, to give emphasis to a feeling or a situation.
In The Slum
tudo se convertia em comendas e crachás; até os modestos dois vinténs de manteiga, que media sobre um pedaço de papel de embrulho para dar ao freguês, transformava-se, de simples mancha amarela, em opulenta insígnia de ouro cravejada de brilhantes, everything turned into commendations and badges; even the modest two vinténs of butter that he measured on a piece of wrapping paper for the customer turned, from a simple yellow stain, into an opulent gold insignia set with diamonds
The narrator deliberately exaggerates the butter into an "opulent gold insignia set with diamonds", and the excess reveals the delirium of someone who cannot think of anything but the neighbor's title.
Chapters X to XI: The Baron's Title, the Razor Slash, and Pombinha's Visit, the narrator