A being of frightening and inhuman appearance and/or demeanor, and quite possibly inhuman origin.
A term so broad and popular for work titles that we had to write this page to cover all our bases (and The Other Wiki covers even more of them than we do).
Monster - A manga and anime written by Naoki Urasawa about a doctor who must hunt down a serial killer he feels responsible for letting loose on the world as a child.
Monster - A 2003 American film Based on a True Story about a female serial killer played by Charlize Theron with nothing at all in common with the above anime. It won Theron several awards including an Oscar Award and Roger Ebert called it one of the best films of that decade.
Monster - A book about a guy named Monster Dionysus trying to survive real life around his job of capturing cryptozoological monsters while putting up with a girlfriend who's a real monster.
Monster Hunter, a popular video game series that bears some semblance to the above, but replaces the cute monsters with big nasty dinosaur monsters and the Gotta Catch 'Em All with "kill or be killed".
Complete Monster, a YMMV item about a villain who is the most degenerate in a work, provokes fear or hatred in all the characters and is completely devoid of redeeming features.