Giant animals

A giant animal is an animal whose size and mass is significantly greater than the maximum size of a normal animal of it's respective species. Which is to say, such an animal cannot possbily exist in nature. Some animal species that are extraterrestrial in origin may appear to be giant-sized, but it is quite possible that this is actually the appropriate size for it's species.

The science fiction genre in particular, has always nursed an affection for giant animal stories and as such, is actually a sub-genus (if you will) of the giant monster trope. In film, animals of extraordinary size usually come about as a result of an adverse change to the environment. More often than not, this adverse change is usually caused by humanity's abuse of either science or the ecosystem. Dumping a canister of toxic waste into a reservoir is a surefire way to breed all manners of giant animals.

In film

 * Attack of the Giant Leeches: In the 1959 "creature feature" Attack of the Giant Leeches, a race of oversized leeches are discovered living in a cavern in the Florida Everglades. The origin of this mutated breed of creature is unknown, but they sustain themselves by attacking locals and bringing them back to the caves where they slowly drain them of blood until they are dead. These attacks attract the attention of game warden Steve Benton, who enlists the aid of Florida State troopers to track the leeches back to their lair and destroy the cave with dynamite explosives.


 * Eight Legged Freaks: In the 2002 film Eight Legged Freaks, a truck driver accidentally spills a canister of toxic waste into a reservoir in Prosperity, Arizona. Insects that are exposed to the toxic waste are later consumed by spiders, which in turn, causes them to grow in size ranging from a foot in diameter to eight feet high.


 * Frankenstein Conquers the World: A mutant dinosaur creature named Baragon appears in this film, but he is actually more of a giant monster than a dinosaur since he does not appear to be any known species of dinosaur on record. In the international release of the film, the Frankenstein Monster defeats Baragon and then plummets to his doom from the top of a high peak after wrestling around with a giant mountain octopus. Yes, you read that correctly... a mountain octopus.


 * King Kong Lives: King Kong himself is a giant gorilla, who has the good fortune to find himself a mate, equally giant-sized and together they spawn a giant-sized ape baby.

In video games

 * Resident Evil: The Umbrella Corporation creates the T-Virus, which escapes and has a mutagenic effect on various animals, including causing a snake to grow to enormous size. The snake is dubbed "Yawn" due to the way its mouth extends.

Appearances

 * Resident Evil (VG)
 * Resident Evil: Deadly Silence