Thumper

Thumper is the secondary antagonist in A Bug's Life.

A Bug's Life
Thumper is Hopper's "pet," so to speak. He is feral, vicious and almost dog-like (and also attached to a leash collar). Thumper is somewhat Hopper's bouncer, brutally beating up any insect who stands up or disobeys Hopper.

When Thumper is first seen, he threatens Dot, prompting Flik to defend her.

Many months later, Flik stands up to Hopper again and is beaten up by Thumper as punishment. Flik survives the ordeal and continues his standoff. Out of nowhere, Hopper attacks Flik, making him fall to the ground, and then he tries to squash his head, only to be stopped by Princess Atta. Then, the rest of the colony chase off the grasshoppers. Thumper tries to scare Dot, but she smacks him, calls him a bad grasshopper, and tells him to go home. Then, he angrily roars at her, but Dim appears behind Dot and roars louder than Thumper, making him race off after the other grasshoppers yelping like a dog.

Personality
He does not speak in the actual movie (in which his sounds are provided by Frank Welker). However, in one of the bloopers, he is revealed to be intelligent and can speak. As he is roaring at Dot, he stops to rethink on how he could do better, in which he says, "I'm sorry, I'm sorry. Can we cut? It's just that I don't think I'm coming across. Hmm. Oh! Oh! I know! I know! I could lather up a bunch of spit. Ooh, ohh, that's good. I got it, J.L. All right, one more for me.", in which David Lander did his voice.

Trivia

 * The blooper reel which appears during the credits for A Bug's Life contains a blooper which is the only time where Thumper actually speaks, and was voiced by David Lander.
 * He was named after Thumper from Bambi who is one of John Lasseter's favorite Disney characters.