GameShark for the Nintendo 64 is a video game cheat device, not a game itself, used to unlock and manipulate various aspects of N64 titles. It plugs directly into the console and allows players to enter codes that can alter game data in real-time, providing advantages like infinite health, unlimited ammunition, unlocking hidden features, and accessing levels or items that would otherwise require extensive gameplay to obtain. This hardware empowers gamers to customize their experience, experiment with games, and enjoy a more casual or differently challenging playthrough. It falls under the genre of utility/gaming enhancement.