As a child, Nora originally built Lil Acorn as a defense drone for a science project, until she developed an interest in talent shows. She then modified him to use him as an animatronic ventriloquist dummy, pretending to be his puppeteer. After doing many shows with Nora, Lil Acorn soon grew to love showbiz, but his ego got carried away, and he started to abuse and threaten Nora, eventually taking the stage of fame for himself. However, without Nora acting as a puppeteer, his audience rejected him, calling him an abomination, and chasing him into the wilderness until his battery ran out of power. Lost in the woods for years, Lil Acorn had some of his parts missing due to deterioration, water damage, and exposure to beavers. Lil Acorn became bitter and alone, blaming his misfortune on his creator.
After being discovered in the forest and repowered by a child, he escaped and went off to hunt down Nora. He sought revenge on her for abandoning him, and longed for her to create a bride for him. After Jenny came to protect her mother from Lil Acorn, he falls in love with her and decides to make her his bride, overpowering her using his army of puppets. At their wedding, Nora distracts Lil Acorn, and while he is singing a “never-ending” song to torment her, she sneaks up on him and finally turns him off. Nora initially wanted to destroy him after deactivating him, but Jenny feels pity for the robot puppet, knowing that he is lonely. Lil Acorn is then released back into the forest with Tuck's sock puppet, Lucretia, who becomes his bride. No longer bitter and vengeful, Lil Acorn is reformed, and lives a happy life with his new sock puppet bride.
Lil Acorn was initially cheerful and funny, and was good friends with his creator, Nora. But he grew megalomaniacal and cruel after so much success on stage, and threatened Nora to let him go and perform comedy acts on his own (or else he would torture her by singing “The Song That Never Ends”). After he was rejected and deemed an abomination and a freak by his former audience (seeing as he didn’t have a puppeteer), Lil Acorn got lost in the wilderness, where he became bitter, vengeful, and lonely. However, Jenny has pity on him, knowing his cruelty stems from his loneliness. When he is given Tuck’s sock puppet, Lucretia, as a bride, he is reformed, and returns to his cheerful old self.
- Lil Acorn's grotesque appearance, wicked, megalomaniacal mannerisms, and ability to put other puppets under his control and act as his henchmen in order to intimidate and manipulate humans, are extremely similar to the living dummy, Slappy, from R.L. Stein's Goosebumps children’s horror series, namely the “Night of the Living Dummy” and its many sequels.
- Lil Acorn’s episode, Puppet Bride, closely parodies many of the “Night of the Living Dummy” stories, including “Bride of the Living Dummy”.