In video games, a boss is a particularly large or difficult computer-controlled character that has to be defeated at the end of a level, episode or game. Bosses appear in many video games, including story-based or level-based first- and third- person shooters, platform games, many role-playing games, and most shoot 'em ups.
Many single-player games feature a level/episode structure, the game becoming progressively harder as the player advances. Bosses are a consequence of this structure, appearing at the end of a level or episode, and being the hardest enemies to defeat. Others have a storyline and no level-based structure, but still feature boss-like enemies at various points in the story or at the end of the storyline.
Games make bosses difficult to kill by giving them more hit points (amount of damage they can sustain) and more effective attacks. In complex games, bosses also have "special" attacks, such as stunning/freezing the player, teleportation, or curses that decrease attack, armor etc.
