Stucky (ぬけないくん, Nukenai-kun)is a boy hamster, who loves hide and seek. He appears as the main character in only three episodes but is generally a supporting character elsewhere. He makes cameos in a couple episodes. He is like Cappy in a lot of ways. They both like to play hide-and-seek and are smaller than most of the other hamsters in the show. In fact, judging from the size of his pipe, he might be the smallest hamster in the show, or at least tied with the Hambini. Stucky appears in the video games Hamtaro: Rainbow Rescue and Hamtaro Ham-Ham Games.
Stucky shares many characteristics with Cappy, including his looks, voice and speech patterns. Stucky is "stuck" in a plastic pipe, so he can only move by running or rolling, but he likes being "stuck". His pipe resembles a warp pipe from the Mario series both in shape and colour, so he always rolls around saying "Roly-poly" (Korokoron in Japanese). Stucky is a hamster who has a large family and is the opposite of Cappy when it comes to life at home. There are so many kids in his family, no one really notices him, and that's why he is always hiding. He loves hide-and-seek and is really good at it too. Cappy, at first, didn't like him because of that, but when Stucky found Cappy after he had been in danger, they became the best of friends as both feel that at times they can be left out of their main group of friends. Stucky never said where he lives.