Distrobox is a tool that allows users to run any Linux distribution inside their terminal, providing a mutable environment on an immutable OS and enabling the use of different distributions for specific tasks. It uses podman, docker, or lilipod to create containers that are tightly integrated with the host system, allowing for shared access to the user's home directory, external storage, and graphical apps. Distrobox aims to bring any distro userland to any other distro supporting podman, docker, or lilipod, and is implemented as a single statically-linked Go binary. The tool has various use cases, including testing, development, and gaming.