A monster is any creature, usually found in legends or horror fiction that is often hideous and may produce fear or physical harm by its appearance and/or its actions. The word "monster" derives from Latin monstrum, an aberrant occurrence, usually biological, that was taken as a sign that something was wrong within the natural order.
Definition of a monster
Among newborn young and embryos of man and most species of animals are found occasional individuals who are malformed in whole or in part. The most grossly abnormal of these have been referred to from ancient times as monsters, probably because the birth of one was thought to signify something monstrous or portentous; while the less severe are known as abnormalities or anomalies or even birth defects. No sharp line separates these grades of malformation, all being due to various kinds and degrees of modification of the normal course of development of the embryo.
Victor Frankenstein builds the creature in his laboratory through an ambiguously described scientific method consisting of chemistry and alchemy. The creature horrifies Frankenstein, and the scientist immediately disavows the experiment. Abandoned, frightened, and completely unaware of his own identity, the monster wanders through the wilderness searching for kindness and acceptance.
He finds brief solace in a woodshed beside a remote cottage inhabited by a family of peasants, the DeLaceys. Eavesdropping on the family's conversation, the creature familiarizes himself with their lives and comes to regard them as his own family, referring to them as his 'protectors'. He learns to speak by listening to the family teach French, their native language, to an Arabian daughter-in-law, and the creature becomes eloquent, educated, and well-mannered in a short time.
After much deliberation about revealing himself to the family, the creature introduces himself to the patriarch, the blind father, and who accepts him into his home and treats him with kindness. The blind man cannot see the creature's "accursed ugliness" and considers him a friend. When the rest of the family returns, they are terrified of the creature and drive him away. Still hopeful but bewildered, the creature rescues a peasant girl from a river, but is shot in the shoulder by a man who claims her. Heartbroken and enraged, the creature renounces all humankind, swearing revenge on his Frankenstein, for abandoning his grotesque creation to a cruel and intolerant world.
Meanwhile, Frankenstein exiled himself to the mountains to reconcile his grief and despair. The monster approaches him at the summit and insists Frankenstein hear his plight. The creature tells Frankenstein his story, while also pleading with his creator to manufacture a female equivalent to mitigate the loneliness of his existence. Frankenstein agrees, but, aghast at the possibility of creating a race of monsters, abandons the agreement preceding the female creature's completion and enraging the monster. Before fleeing into the night, the creature threatens Frankenstein saying, "I will be with you on your wedding night!"
Later, the creature kills Frankenstein's best friend, Henry Clerval, and his bride, Elizabeth Lavenza. Due to the incident, Frankenstein's father dies of grief. Frankenstein then dedicates his life to hunting and destroying the product of his experiments. Searching for the creature in the Arctic Circle, the scientist loses control of his dogsled and falls into the freezing water, contracting severe pneumonia. A ship exploring the region rescues Victor. Before succumbing to his illness and dying, he relates his entire story about the creature and his experiment to the captain, Robert Walton. Later, the creature boards the ship, intent on taking his final revenge, but, upon finding his creator dead, is overcome with grief. The monster pledges to travel to "the Northernmost extremity of the globe"; he leaps from the boat and disappears.