The scale model of the Candy Kingdom is a gift Finn planned to give to Princess Bubblegum to celebrate her Science Barbecue. It is made out of Finn's saliva bubbles, and is made on a pink tray.
In "The Real You," Finn tells Princess Bubblegum to close her eyes as he presents the model to her, but she unknowingly sneezes the model's bubbles away. Finn tries to rebuild it in a panic before Princess Bubblegum opens her eyes, telling her to wait a few hours. Princess Bubblegum soon gets tired of waiting, however, so she opens her eyes and sees the pink tray that the model was originally on. She assumes this is Finn's gift. Princess Bubblegum never sees the model, but she is nonetheless pleased with the tray because she loves pink objects.
