A
comic that runs only for a set (usually less than ten) number of issues. One of the
advantage with this format is that the
writer has a great level of freedom and can do things like killing off main characters or change things in drastic ways. One of the first successful miniseries was
Camelot 3000 by Mike W. Barr and
Brian Bolland, which did just that.
Often, the characters for a miniseries are created just for that purpose, but sometimes already existing characters are used. In that case the story is often set in an alternate universe or in the future ("Kingdom Come" and "Batman: The Dark Knight Returns" both do this) to give the writer more freedom.
Often, the miniseries become so popular they spawn spin-offs (usually of lower quality and not by the original author). This happened to The Books of Magic for example.