Lumpawarrump, also known as Lumpy, is Chewbacca and Malla's son.
When Stormtroopers invade the Wookies' house during Life Day, they break Lumpy's toys searching Rebel devices, and then send him back to his room to keep him busy. There, he watches a cartoon about the Rebels' adventures (but we must pretend he's playing an unrelated videogame when he's almost found).
When the cartoon finishes, Lumpy works to create a translation device from his Amorphian machine that will fool the Imperials into returning to their base by faking their commander's voice. However, one Stormtrooper remains behind, finds Lumpy tricked them and chases him. As they both run onto the deck, Han and Chewbacca arrive. Chewie protects Lumpy as Han dispatches the stormtrooper.