Evil Is Petty: When his big elaborate plan fails, he settles for mercilessly beating up Flik and trying to murder him. In fact, his only reason for going back was to kill one ant who was no apparent threat and only hurt his pride.
For the Evulz: It becomes clear that his actions are only because he is a violent sociopath who enjoys inflicting pain.
Freudian Excuse: Averted ruthlessly. Unlike other Pixar villains, Hopper has no known "reason" behind his twisted acts. He's just a bully, plan and simple.
Genius Bruiser: He can easily beat down most anybody else in the film, but he's still hardly dumb. He knows that if all the ants stood up the grasshoppers that since they're far more numerous, the ants would easily push them away. And indeed does happen, they just needed a push.
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!"
Idiot Houdini: Despite the fact that he changes his attitude in the end, he never really gets his comeuppance for some of the bad things he (unwittingly) did in the film. Though he is tied up and set on fire at various points.
Unwitting Instigator of Doom: He's responsible for the ants finding out the circus bugs aren't warriors, costing Flik his newly earned good name. To specify, he's responsible because 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.