Answer:
In literature, when the author uses exaggeration/oversimplification of certain character traits, it is referred to as a caricature. Often insulting, caricatures can also be complimentary or even have a political purpose.
In George Orwell's political allegory, Animal farm, Squealer is one of the three most important animals who rebel against their human farmer. Squealer comes as a clever character with good persuasion techniques. He is, however, quite selfish and power-hungry (like most of the leaders). The very fact that he is described as having a difficulty with seeing "out of his eyes" speaks volumes about both his physical appearance and personality. He is a very fat pig, indeed, but he also only cares about his own interests.
