Traditional MUDs implement a role-playing video game set in a fantasy world populated by fictional races and monsters, with players choosing classes in order to gain specific skills or powers. Players typically interact with each other and the world by typing commands that resemble a natural language.
Players can read or view descriptions of rooms, objects, other players, non-player characters, and actions performed in the virtual world. MUDs combine elements of role-playing games, hack and slash, player versus player, interactive fiction, and online chat. A MUD ( / m ʌ d/ originally multi-user dungeon, with later variants multi-user dimension and multi-user domain) is a multiplayer real-time virtual world, usually text-based.