Is this an idiom?
"that would only add fuel to the flames" - catching fire

if it isn't then is it another literary device?

Read the excerpt from the war of the worlds, in which the first martian exits the spacecraft. a sudden chill came over me. there was a loud shriek from a woman behind. i half turned, keeping my eyes fixed upon the cylinder still, from which other tentacles were now projecting, and began pushing my way back from the edge of the pit. i saw astonishment giving place to horror on the faces of the people about me. i looked again at the cylinder, and ungovernable terror gripped me. i stood petrified and staring. what option accurately analyzes the impact of the narrator's thoughts and actions on the tone of the excerpt? the war of the worldsa disdainful tone is created as the narrator ponders the ugliness of the tentacles and turns to the shrieking woman. a melancholy tone is created by the narrator's thoughts of fear and refusal to avert his eyes. a tone of determination is created when the narrator thinks of escape and backs away from the edge of the pit. a fearful tone is created through the narrator's thoughts of horror and his glance at the cylinder.