Giant Squid

Aside from being a plentiful source of low grade calamari, Giant Squid are just as appetisingly useful for their role as Sea Monsters roaming the deep, attacking boats full of Cutthroat Island extras and being an all round menace to the high seas.

As a real life species, giant squid are believed to have inspired Norse tales of the Kraken and as one of The Oldest Ones in the Book had a lot of overlap with the epic Kraken and Leviathan. After Jules Vernes's Twenty Thousand Leagues Under the Sea, the Giant Squid became a much more of a monster in the vein of any other "Gigantic Animal" monster: much more explicitly a larger version of something already known, scientifically unstudied but explanable and belonging to a realm not yet fully discovered, in this case, the depths of the sea.

Being mostly tentacle, the Giant Squid has a variety of ways in which it may be depicted on screen. You might see only the tentacles, perhaps the top of the head occasionally peaks out of the water. A full body shot may be a climatic reveal and seeing the beaked mouth may be reserved for the death scene of some poor sucker being slowly dragged into it. Very often the tentacles almost seem to act as their own monster following the principle of only taking what is on screen as being real.

Authors, designers and illustrators not always being sticklers for accuracy, the trope Giant Squid includes giant octopuses and giant-sea-creatures-that-are-some-weird-hybrid-of-squids-and-octopuses, as well.

Subtrope of Sea Monster, see also Giant Enemy Crab and Everything's Squishier with Cephalopods.

Examples of Giant Squid include:

Films -- Animation

The sequel to Disney's Peter Pan replaced the tick-tocking crocodile with a giant orange octopus which made popping noises.

Films -- Live Action

The Kraken from Pirates of the Caribbean. Though far bigger than any real squid (thereby really earning its Kraken title) it still is very specifically squid in design from its tentacles to its eyes and beak.
Mega Shark vs. Giant Octopus Changing it to an Octopus was the closest to originality the film got.
Reap the Wild Wind feature John Wayne fighting and being killed by a rather silly looking giant octopus
Roger Corman's first film was Monster from the Ocean Floor, and featured a female marine biologist vindictivly hunting a giant squid.
Beneath the 12 Mile Reef has a giant human attacking octopus
Mysterious Island and It Came From Beneath the Sea were both Haaryhausen animated movies with giant killer cephalopods in them.
Voyage to the Bottom of the Sea has a gigantic octopus in it.
What are initially believed to be numerous worm-like creatures in Deep Rising that infested the ship and consumed the entire crew and its passengers actually turn out to be the tentacles of an extremely large squid-like monster at the end.
Boga Ten in Road to Bali.
In The Lord of the Rings films the Watcher in the Water was decidedly squid-like with bits of octopus thrown in for good measure. In the books the description is a bit more vague but still retains most of the Giant Squid properties.
The Walt Disney version of Verne's 20,000 Leagues Under the Sea prominently featured a giant squid that Kirk Douglas went mano a mano (a mano, a mano, a mano...) against with a harpoon.

Literature

To be elaborate on Twenty Thousand Leagues Under the Sea, the crew of the Nautilus (and Ned Land) fight a giant squid that has wrapped itself around the submarine. It is the most recognisable point after Nemo and the Nautilus themselves and is a standard fixture in any adaptation.
The giant squid from Harry Potter. It seems to care about the students, as on one occasion Fred + George are seen tickling it, and on another it puts a first year who had fallen into the lake back into the boat.
Michael Crichton's posthumously published Pirate Latitudes features two encounters with what is presumably a giant squid, which the characters call a "Kraken". The first one doesn't do much and is quickly forgotten. The second one is strangely aggressive, grabbing crew members and flinging them overboard. It also, for some reason, has bioluminescence.
- Another Chricton novel, Sphere, also features a giant squid as a manifestation of a character's mind.
The narrator of Moby Dick has an encounter with a giant squid:

Almost forgetting for the moment all thoughts of Moby Dick, we now gazed at the most wondrous phenomenon which the secret seas have hitherto revealed to mankind. A vast pulpy mass, furlongs in length and breadth, of a glancing cream-color, lay floating on the water, innumerable long arms radiating from its centre, and curling and twisting like a nest of anacondas, as if blindly to clutch at any hapless object within reach. No perceptible face or front did it have; no conceivable token of either sensation or instinct; but undulated there on the billows, an unearthly, formless, chance-like apparition of life.
As with a low sucking sound it slowly disappeared again, Starbuck still gazing at the agitated waters where it had sunk, with a wild voice exclaimed -- "Almost rather had I seen Moby Dick and fought him, than to have seen thee, thou white ghost!"

Peter Benchley's Beast, later adapted into a film starring William Peterson called The Beast, could roughly be described as Jaws with a Giant Squid (especially since Benchley wrote Jaws) with the giant squid attacking boats after foolish mankind overfished its normal prey and accidentally killed its young. Mankind's hubris concerning nature leads to him getting attacked by a wild creature? Naaaawh!
Artemis Fowl is attacked by a giant squid in The Atlantis Complex.
In the first James Bond novel - Dr. No - the title character puts him through a torture labyrinth ending with an apparent escape only to be attacked by a giant squid. Improbably, Bond wins.

Live Action TV

A really, really Giant Squid is worshipped as a god on a planet where the Doctor and Romana seek the Key to Time in the Doctor Who serial The Power of Kroll.

Music

The Jonathan Coulton song "I Crush Everything" is sung from the perspective of a giant squid. It suffers from extreme loneliness, because (as the title hints) it can't touch anything without dragging it down to the bottom of the sea and destroying it. And it really hates dolphins. So, sad cephalopod.
Alestorm's "Death Throes of the Terrorsquid" is a song about... Pirates killing the terrorsquid.
The video for Lindsey Stirling's "Master of Tides", performed live flash-mob style in the fountain at Glendale, CA's "The Americana at Brand" shopping center, includes massive tentacles projected on a screen behind her, and the shadows of more tentacles projected on a mist generated between her and the screen.

Politics

In 2005 the UK Independence Party or UKIP, a Euro Sceptic party, decided to portray the EU as a Giant Blue Octopus attacking London with Combat Tentacles in this Party Political Broadcast.

Tabletop Games

The New World of Darkness has the Leviathan, the Kerberos of the Sea of Fragments. It's actually only a guess that it's a cephalopod based on the fact that it has tentacles—it's too huge for anyone to ever see what it really looks like.
Dystopian Wars takes this up to eleven - the Empire of the Blazing Sun have the Ika class Mechanical Squid - a gigantic robotic squid large enough to grab and drag down the largest warships into the briny depths.

Video Games

One of Ecco the Dolphin's more random enemies are giant ~~octopodes~~ Eight-Arms. There's plenty of pointy ammonites in Prehistoria, too.
One of the optional ship battles in Skies of Arcadia is against a giant flying squid.
In Command & Conquer: Red Alert 2 the Wacky Soviets have giant squid that can drag enemy ships down to the briny depths. Too bad they traded those in for war bears in part 3.
One of the bosses in Resistance 2 is a huge, many-tentacled Kraken.
The giant pink squid thingy Crusher from the third Sly Cooper game starts off as a boss fight before the Guru manages to talk it into temporarily joining you. You later control Crusher to defend Bentley by smashing pirates in a fashion in a scene that is best described as "Giant Squid Bongo with a Body Count".
One of the recurring enemies in Super Mario Sunshine is a giant squid with a cork in its mouth that sprays polluting ink everywhere.
The final Bonus Boss of Warship Gunner 2 is a giant squid that can sink ships with a blast of high-pressure ink or lasers. But it's a giant, flattened and dried squid.
The Endless Ocean games both feature giant squids in their respective abyssal zones. The second game also has the giant squid's baby, Kraken Jr., who's only a couple of feet long and amazingly adorable for a squid.
The World of Warcraft expansion Cataclysm has Ozumat, a creature working for the Old Gods and able to take on a Physical God.
Story mission nine in Jaws Unleashed opens with a fight against one.
Even though it looks more like an octopus, Lusca from City of Heroes probably counts. There's no way to gauge how big it is, since you can't see the whole thing, but the amount of tentacle that you can see looks to be around 30 feet or more.
One level of Zack and Wiki revolves around taking one down.

Web Comics

Girl Genius has that one time in Paris when someone had a scheme to raise giant squid in the sewers.
- And the mechanical squid in the cisterns, because after all where else would you keep your mechanical squid?
- And the giant winged squid attacking Castle Wulfenbach.
To destroy Lord Hinjo's private ship in Order of the Stick, Redcloak summons a giant octopus. It was eventually defeated by a shark-mounted paladin.
Schlock Mercenary includes a giant squid in the "Touch and Go" arc winding up here.

Western Animation

In The Fairly OddParents, an episode had Timmy, Cosmo and Wanda visiting Atlantis, where their immediatly arrested because Cosmo was responsible for sinking the continent. Timmy, having Wet Willie powers, attempts to summon a giant squid to help them, to which everyone laughs, thinking it doesn't exist. At the end of the episode, the squid finally shows up and destroys Atlantis.
Rocko's Modern Life has a giant squid who is attracted to cheese.
Family Guy. The Griffins defense against it is ignoring it.
In Wakfu, a giant black ~~squid~~ kralamoure is protecting Oma Island by destroying in its tentacles any ship coming too close. It is in fact the form chosen by an ancient shapeshifting dragon.

Real Life

The Giant Squid... and Colossal Squid. Yes, they do exist. While a few stories circulate of boat being attacked by large squid, these creatures are mainly deep water dwellingcreatures, that mostly eat smaller prey. There have been reports of Giant Squid toothmarks on Sperm Whale skins which indicate that the two species regularly fight each other, but since Sperm Whales actively hunt them, these wounds may have been inflicted in self defense.
Meanwhile, the largest octopus in the ocean is the Giant North Pacific octopus, with an arm-span of seventeen feet. There is not as far as most scientists are concerned, any octopus of giant squid-sized proportions or whale-sized proportions, as urban legend seems to state.
The Humboldt squid, while not a large squid (5-foot long mantle) best fits this trope in it's behavior. In California and Baja, where the squid are fished for, it's gained a nickname amongst the fishermen. Diablo rojo, which means "red devil". It does not sink boats, but when feeding or being fished up, they are extremely aggressive. Their beaks are too weak to break bones, but their strong arms have sharp teeth which can rip through skin and most wetsuits. They have also been known to attack underwater cameras and will eat other wounded Humboldts. However, outside of feeding and being fished, they have also been observed to be calm and curious, so their behavior is a subject of debate. Regardless, underwater cameraman Scott Cassell—who made a career filming them—won't go in the water with them without wearing a chainmail wetsuit.
The Staten Island Ferry Disaster Memorial. An elaborate hoax by a local artist which as appeared intermittently in New York City's Battery Park (and elsewhere) since 2016, this is a monument to the Cornelius G. Kloff, a Staten Island ferryboat allegedly dragged to the bottom of New York Harbor by large tentacles before dawn on November 23, 1963 -- and all but forgotten by history due to the assassination of President John F. Kennedy just a few hours later.