Bad Boss: As Molt tells the ants during the raid in the film's second half: "You don't want to make him mad. Believe me!" He takes out his frustration at his brother by punching out another member of his gang because of a promise to his mother. Later, he matter-of-factly kills several of his fellow grasshoppers just to demonstrate a point in an argument.
Big Bad: Hopper is the leader of the grasshoppers and without him the others wouldn't even care.
The Bully: He's psychotic and loves picking on weaker species to make himself feel big.
Deadpan Snarker: He is voiced by Kevin Spacey, after all. Throughout the film, he makes dry remarks about anything that annoys him.
Even Bad Men Love Their Mamas: He says that promising mother on her deathbed not to kill Molt is the only reason he has not done so. This could, however, not really be a matter of loving his mother and instead be more of a matter of simply keeping a promise, especially seeing how it just makes him more dangerous, see Bad Boss above
Evil Is Petty: When his big elaborate plan fails, he settles for mercilessly beating up Flik and trying to kill him. In fact, his only reason for going back was to kill one ant who was no apparent threat and only hurt his pride.
Faux Affably Evil: He becomes chillingly polite when about to do something like murdering his own henchmen or preparing to feed children to deranged grasshoppers.
Freudian Excuse: Averted. Unlike other Pixar villains, Hopper has no known "reason" behind his twisted acts. He's just a bully, plain and simple. All in all, he's competing with Lotso from Toy Story 3 for Pixar's most evil villain.
Genius Bruiser: He can easily beat down most anybody else in the film, and he's hardly dumb; he knows that if all the ants stood up to the grasshoppers, since they're far more numerous, the ants would easily push them away. And indeed it does happen, they just needed a push.
Jerkass: Just a wildly unpleasant individual all round.
Jerk with a Heart of Jerk: He gives the impression of being more than a bully when he announces to his men that they're going to spend the rest of the winter partying instead of returning to the ants' island. Then he kills some of his men to make a point.
Kick the Dog: A number of times. One example is him belittling Atta after "the grasshoppers" meal is gone.
Obviously Evil: Domineering presence, strongest of his group, enjoys making people suffer.
Pragmatic Villainy: Zig-zagged: when some of the other grasshoppers point out to Hopper that they have enough food and an easy life without needing to exploit and oppress the ants for food, he kills them and tells the rest that they oppress the ants for its own sake, not for the food. However, Hopper's point is that the oppression is pragmatic if you take a longer view: while individual ants are no threat to the grasshoppers, the ants as a group outnumber the grasshoppers by hundreds to one. If the grasshoppers let up on the pressure at all, the ants may realize their own power, at which point the grasshoppers' leisurely lifestyle ends.
Scars Are Forever: One over his (also likely blind) right eye, which Word of God confirms was inflicted by the first bird that attacked him.
Smug Snake: Big time. He's smart and utterly convinced of his superiority but has no idea how to deal with the unexpected.
Team Pet: Though it's ambiguous whether he's supposed to represent an attack dog or an ax-crazy human, he seems to be this to the grasshoppers to some degree. A blink-and-you'll-miss-it scene shows him begging Hopper for treats and catching a piece of grain tossed to him in his mouth.
Affably Evil: Nice and friendly, even trying to tell funny stories to ants he's menacing. He even gives them a friendly warning during the second raid, having himself made Hopper angry one too many times:
"Do as he says; you don't want to make him mad. Believe me!"
He's responsible for the ants finding out the circus bugs aren't warriors, costing Flik his newly earned good name. He suddenly shows up demanding that his circus bugs return to work for him. This in turn causes the ants to give up on rebelling against Hopper, almost resulting in the villain's victory.
He also ruins the ants' original plan of scaring the grasshoppers off with a fake bird by setting said bird on fire, thinking it to be the real deal.
Big Eater: How he mainly copes with not getting to be a beautiful butterfly.