How to Kill Fictional Creatures

The death of Achilles was not mentioned in Homer's Iliad, but appeared in later Greek & Roman poetry & drama concerning events after the Iliad, later in the Trojan War. Achilles was said to have died from a heel wound as the result of an arrow - possibly poisoned - by Paris. According to a myth arising later, his mother, Thetis, had dipped the infant Achilles in the river Styx, holding onto him by his heel, and he became invulnerable where the waters touched him, that is, everywhere but the areas covered by her thumb and forefinger.

From Hogfather by Terry Pratchett

Harry Potter series by j. K. Rowling. Riddikulus is a spell used against boggarts. The caster must think of something funny while casting this spell. If sucessful, it turns the boggart into whatever the caster was thinking about. First reference was in 'Harry Potter and the Prisoner of Azkaban'

Part of the 11th Labour of Hercules - the apples of Hesperides. Prometheus was chained as a punishment for ridiculing the gods. Each day an eagle would peck at his liver, but the next day the organ would grow back, only for it to happen again. Hercules killed the eagle and, as a reward, Prometheus advised him to send Atlas for the apples.

'The Exorcist' a 1973 American horror film, adapted from the novel by William Peter Blatty, dealing with the demonic possession of a young girl, and her mother’s attempts to win back her daughter through an exorcism conducted by two priests.

Dragon-teeth men were armed warriors, who sprang out of the earth, after they were sowed the teeth of a dragon in the soil. They would immediately attack anyone in their presence. Jason, the hero of the Argonautica, faced these dragon teeth warriors, as did Cadmus.

Edgar / The Bug was played by Vincent D'nofrio in 'Men in Black'. Edgar / The Bug is a giant alien insect who eats a farmer and uses his skin as a disguise.

Ghostbusters film (1984). Causes total protonic reversal. Gozer the Gozerian, also known as Gozer the Destructor, Volguus Zildrohar, The Traveller, is a Sumerian shapeshifting god.

'2001: A Space Odyssey'

Immortals are a group of fictional characters seen in the movies and series of the Highlander franchise. Since they are immune to disease and stopped aging after becoming Immortal, they can live forever and they only die when they are beheaded.

'The Lion, the Witch and the Wardrobe'.

'...it was beauty killed the beast...' Of course falling off a very high building doesn't help.

'The Mummy'

'Dr Who'

In Terminator 3, the Terminator refers to itself as a "T-101".

A stake should be 2' long and made of hawthorn preferably, a quiver of stakes is suggested for close combat

Jumanji (1995)

'Wizard of Oz'. Actually, this method works surprisingly well on lots of things...

'Wizard of Oz'

You have to destroy its brain. A bullet to the head, beheading, blugeoning and exploding have all been found effective apparently.

A bullet to the head, beheading, blugeoning and exploding have all been found effective apparently.