Fighting the Beasts

A recurring theme in many a story, usually fantasy, science fiction, superhero, and horror films, there is a time when the hero or heroine has to stand up against a monstrous creature. He or she does this for these reasons: The most common image of fighting a beast is a knight facing a fire-breathing dragon to rescue a princess.
 * To protect himself
 * To save someone (usually a damsel in distress, his family and friends, or someone he/she loves)
 * To save his homeland
 * For glory and/or honor
 * To prove his worth
 * To obtain a sacred treasure

Examples

 * Hercules fights the multi-headed Hydra.
 * Luke Skywalker fights Jabba's Rancor.
 * Metroplex fights Trypticon.
 * Robert Smith (South Park) fights with the help of The Boys of South Park Mecha-Streisand from destroying South Park.
 * Rexy and the raptors fight the I-Rex.
 * Ron Weasley and Harry Potter battle the Mountain Troll to save Hermione Granger.
 * Bambi kills one of Man's dogs, kick him and making fall on The mountain.
 * Saitama fighting Carnage Kabuto
 * Harry Potter fights the Basilisk in the Chamber of Secrets.
 * Neville Longbottom kills Nagini the Snake
 * Hermione Granger and Harry Potter battle Nagini at Godric's Hollow
 * Giselle fights Queen Narissa to save Robert Phillips.
 * Prince Phillips fights and slays Maleficent in her dragon form.
 * Danny Phantom fights Prince Aragon in his dragon form.
 * Wolf Predator fights Predalien on top of the rooftop.
 * Godzilla fights M.U.T.O.
 * Spike stands up to Scar Snout to protect the Rugrats Gang.
 * The Guardians of the Galaxy battle the Abelisk to save batteries.