Skeletons are a common variety of monster in Dungeons & Dragons. They have been around since the earliest edition of the game and were predominantly created from human bones to begin with, but later editions have come to include other skeletal enemies as well.
A skeleton is a mindless automaton consisting of dead bones that have been reanimated through black magic. They have no will of their own and blindly serve whoever reanimated them, carrying out simple labour or attacking their masters' enemies. Armour and weaponry tend to vary since skeletons usually just use whatever remains of the equipment they carried when they were alive. When ordered to carry out a task, the skeleton will continue said task until ordered to stop or has been destroyed.