Role in the film
Russ' younger brother, Ron, accidentally hits a baseball through the Szalinskis' attic window and activates their shrinking machine. He, Ron, and the Szalinski children, Amy and Nick, go up there to retrieve it. Luckily, it got stuck in the machine and blocked one of the laser components, resulting in it only releasing enough energy to shrink things. The four kids, a nearby couch, and chair are shrunk by the ray when it fires.
As Wayne Szalinski comes home from a presentation at the lab, he notices his kids and "thinking couch" missing. Without an explanation for this occurrence, he begins to get angry with the machine. He begins to destroy it as the kids, now 1/4 of an inch tall, tries to get his attention, but to no avail. He begins to sweep up the mess and accidentally dumps them into the trash with it. They escape from it and find themselves at the far end of the backyard. Knowing that crossing it to get back to the house will take hours at their size, they begin to climb a flower to see how far the house is. While clinging to it, Nick and Russ Jr. are attacked by a bee. They cling to it for dear life and are separated from Ron and Amy.
Russ Thompson, Sr., Ron and Russ Jr.'s father, is getting aggravated at his missing sons since he was planning a fishing trip with his family. Russ Jr., who secretly likes Amy, often feels small compared to his father's standards since he was cut from the football team (although it is revealed later on that he actually quit it) while looking at the attic floor.
Meanwhile, Wayne accidentally turns on the sprinklers while searching for the kids in the backyard. Giant splashes of water soon surround them. Amy begins to drown in the muddy water near the flagstone while Wayne turns the sprinklers off. Russ Jr. saves her before she dies by giving her mouth to mouth resuscitation. The kids continue their journey. During the night Amy and Russ Jr. admit their feelings for each other and share a kiss, but are interrupted by an attacking scorpion.
He was indirectly mentioned in the sequel after Nick told Mandy about his adventures of being shrunken.