Marvel Comics' X-Force was an X-Men spinoff that debuted in 1991 - issue 1 was the single largest selling issue of a comic ever. (Editor's note: This record was soon surpassed by other comics, like Spawn #1 and X-Men #1.) As well as being well hyped issue one was sold with each issue having one of a series of Collectors Cards that meant collectors bought up multiple issues. The team was made up of characters from the New Mutants with a more militant approach to Professor X's dream of human/mutant coexistence. The engine for this change was Cable joining the New Mutants near the end of the books' tenure.
X-Force was originally pencilled by Rob Liefeld who quit the book after 9 issues to form Image Comics along with 6 other creators (Todd McFarlane, Jim Valentino, Marc Silvestri, Whilce Portacio, Erik Larsen and Jim Lee). From there on in X-Force served to confirm all its negative points - It was subject to ostentatious crossovers, the writing, art, plot and characters all sucked and it existed solely for being an X-Title. This dead horse was flogged until 2001 and then writer Peter Milligan and artist Mike Allred took over.
Milligan and Allred recreated X-Force as a celebrity super-team made up of mutants who went on televised high risk missions where members get killed day in day out. They reinvigorated a title that had gone nowhere into a highly enjoyable book that is one of the most intelligent and readable comics Marvel has ever published. This new look also led to Marvel dropping the Comics Code- an outmoded method of comics industry self censorship. Within 2 years this new X-Force was relaunched as X-Statix and it continues to be a thoughtful look at the media and celebrity. It also features cult favourite Doop, a strange yet cute mutant who resembles Slimer from Ghostbusters and films their adventures.