One day, Dwayne arrived and tried to kill Ozzie (who had faked dying), but the opossum fled into the hedge. Dwayne then smells Verne (whom he calls "Reptile") and bends over to capture Verne (who is under a car), but Verne already escaped back into the hedge to meet up with the other animals.
Dwayne installs a high-powered extermination system in Gladys' backyard, figuring she would insist on wanting it, regardless of its illegal status.
Later, when Gladys catches the animals in her house, Dwayne arrives and is able to capture the animals except RJ, who left to return the food to Vincent. Dwayne mockingly tells Verne he has just been "verminated". When RJ sees Dwayne driving away with RJ's caged friends, the raccoon has a change of heart at the last moment and decides to go save them. The impact knocks Dwayne out and frees the animals, who turn the van around to go back home. Meanwhile, RJ is chased by Vincent atop the van. Verne eventually manages to convince the other animals that RJ is trying to help them and they all turn to help RJ defend himself from Vincent. With no control, Dwayne's van eventually makes a jump and flies through Gladys' house. As Dwayne regains consciousness, RJ and the others flee into the hedge, with Vincent on one side trying to claw them and Gladys (who uses a weed hacker) and Dwayne (who uses a cattle prod to shock the animals) on the other. RJ and Verne then get an idea and have Hammy drink some soda and he makes the whole world freeze. After that, Hammy walks into Gladys' backyard, activates the Depelter Turbo, and then gets an idea and puts a little garden gnome behind Dwayne's foot. RJ, borrowing Verne's shell, uses himself as bait to lure Vincent into Gladys' backyard. Vincent, Gladys, and Dwayne fall into a pile as the Depelter Turbo comes on-line (due to them falling into the lasers), stinging them all.
Gladys and Dwayne are arrested for illegal traps. While Gladys fights the cops and beats them up, Dwayne quietly escapes and climbs over a fence, only to be bitten on the leg (presumably) by Nugent after stepping on one of the rottweiler's squeaky toys.
It is unknown what happened to Dwayne after the events of the film, but it could be possible that the police eventually found and arrested him, along with Gladys.
Dwayne is mean, rude, selfish, over-zealous, and conniving. Dwayne seems to have a crush on Gladys, but she doesn't like him very much.
Dwayne calls Gladys "Nancy" in a funny way to stop her complaining.
He is also very sarcastic.
- Dwayne is often thought to be the main and secondary antagonist of the film. This is not true as Dwayne was simply following Gladys' orders and is less unscrupulous than Vincent and Gladys.
- Throughout the film, Dwayne appears to have a crush on Gladys, despite her never returning the sentiment as she finds him rather annoying.
- For some reason, Dwayne refers to Gladys as "Nancy."
- He is called "The Sniffer" by the animals because he can sense what kind of animal is surrounding him.
- Dwayne is the spoof of the Terminator: Both say their catchphrase in Spanish; Terminator says, "Hasta la vista, baby!" while Dwayne says, "Buenos dias, reptile!" (then adds, "Or should I say, Buenas noches!" and laughs evilly).