Final answer:
The literary device used in the quote from "Confederacy of Dunces" is a metaphor, which compares the character's head to a 'fleshy balloon' without using 'like' or 'as.'
Step-by-step explanation:
The literary device used in the quotation "A green hunting cap squeezed the top of the fleshy balloon of a head." from "Confederacy of Dunces" by John Kennedy Toole is a metaphor. A metaphor is a direct comparison between two unlike things without using 'like' or 'as.' In this case, the character's head is directly compared to a "fleshy balloon," which emphasizes its shape and size in a vivid and imaginative way, without using 'like' or 'as.' This comparison allows readers to visualize the character in a unique and specific manner, adding depth to the readers' understanding of the character's appearance.