Shimeji: Screen Buddies by Digital Cosmos introduces a novel category of screen utility applications that overlay animated characters across the Android interface. These digital companions roam freely above other applications, creating persistent interactive elements that transform device interaction into personalized experiences. The app occupies a niche market position between wallpaper utilities and gaming companions, distinguishing itself through character interactivity rather than static display. The application's core functionality centers on its extensive character library exceeding 1,000 options spanning anime, gaming, and internet culture franchises. Characters demonstrate autonomous behaviors including climbing screen edges, interacting with interface elements, and performing unique animations. The customization system allows users to modify character appearances and behaviors, while the creation tools enable designing original characters. These elements remain visible during other application usage through an always-on-top overlay system that maintains functionality across messaging, gaming, and productivity scenarios. User experience demonstrates thoughtful design through intuitive gesture controls and non-intrusive implementation. Characters respond to touch interactions with context-specific animations while remaining movable or dismissible through drag gestures. The notification panel integration provides quick access modes including ghost mode (semi-transparent), normal operation, and complete disablement. Real-world usage patterns show predominant deployment during leisure activities rather than intensive work scenarios, with users typically activating characters during media consumption or casual device interaction. User feedback trends highlight exceptional satisfaction with character variety and non-intrusive monetization. Aydan's July 2025 review praises the 'completely optional' premium model, while Jessica Santiago's July 2025 assessment notes superior ad implementation compared to alternatives. Multiple reviews including Energetic Emo Girl's June 2025 commentary emphasize psychological benefits through 'serotonin boost' descriptions. Technical concerns emerge regarding battery consumption, as noted by Brangeliez Snow's July 2025 observation of tablet battery drain, alongside interaction clarity issues mentioned in min_clara38's July 2025 review regarding movement activation consistency. The application demonstrates strongest implementation as a lightweight digital companion system with particular strength in character diversity and unobtrusive operation. Limitations surface in power management during extended use and occasional animation triggering inconsistencies. Ideal deployment scenarios involve secondary device usage or short-duration engagement where battery impact remains minimal, while character customization features offer substantial value for franchise enthusiasts and creative users seeking personalized digital expressions.