Proportionately Ponderous Parasites

And the great fleas themselves, in turn, have greater fleas to go on;
While these again have greater still, and greater still, and so on.

— Augustus De Morgan

When there are monstrously large creatures roaming the country side, you can expect the things that live on them (be they parasitic or symbiotic) to also be monstrously large, the creepiest of Big Creepy-Crawlies. They may be annoyances for their host, but for humans, they can be deadly. They're often monstrous or mutated just to be able to live on such gigantic life forms.

Keep in mind that some parasites can get pretty large within human hosts (tape worms, etc.). This trope is for parasites that are larger than their normal (read: human and common animal preying) brethren due primarily to their host organism being larger.

A common feature of a Womb Level and often featured living on Kaiju.

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Examples:

Anime & Manga

• After Guts from Berserk cuts his way through the insides of the The Sea God, he's attacked by a swarm of critters resembling long-legged Giant Spiders. According to Schierke, they protect the Sea God in exchange for nourishment.
• In Delicious in Dungeon, when Senshi is cutting open a giant kraken they just killed, a toothed worm the size of a large eel jumps out of the cut. Laios lampshades how "big animals have big parasites too!", but more importantly they're able to make a meal out of the filleted worm, since the flesh of the kraken turns out to be inedible. Laios ends up contracting a painful parasitic infection from trying to eat the parasite's flesh raw (by an even smaller parasitic worm that was parasitizing the large worm).
• The Junji Ito Kyoufu Manga Collection story "Washed Ashore" features a serpentine creature the size of a whale with a head resembling a mass of barnacles and translucent flesh which probably glowed when it was alive. Onlookers see smaller creatures through its clear skin, but in a horrifying twist, its parasites are humans that it consumed, who managed to survive being eaten by absorbing nutrients inside the creature's intestine. Understandably, they've all been driven insane after being trapped inside a sea monster for seven years.

Comic Books

• The Authority: In the final arc of Warren Ellis's initial run, the team is up against a beyond-huge pyramidal space entity that, as a scientist put it, created Earth as a Mordor-esque vacation home, and is not happy to find that life has developed to such a degree. Inside it, the team finds an entire civilization of parasitic lifeforms that build whole cities within the creature. These parasites later hire Lobo to get revenge on the team.
• The comic book Godzilla Legends has Godzilla, again, afflicted with a parasite. This time, it's a bird making a nest amidst its spines. The radioactivity mutated the birds into razor-beaked, multi-eyed freaks.
• Parodied in the Italian comic book Nilus: in a strip a group of Egyptian soldiers try to approach a sleeping Goliath to capture him, but are forced to make a run for it when they're attacked by Goliath's dog-sized lices.
• Silver Surfer: One issue of the 2016 solo has Norrin and Dawn enter the mouth of a truly enormous Space Whale. Inside they encounter its immune system, which are palm-sized sentient organisms, at war with The Plague of equal size.

Fan Works

• In Pokédex, Deoxys turn out to be the parasites of some unknown alien creature, mutated to be able to survive on its own. Considering that said Pokemon is 5'7, not to mention being very powerful, the narrator speculates accordingly on just what its host could be like.

Film — Live-Action

• Cloverfield has its main monster, Clover, beset with extremely dangerous dog-sized "flea"-like creatures living on its hide. Their bite is extremely dangerous and they're about five feet long to boot. If anything they seem to be more dangerous on a personal level than Clover, which is just wandering around in confusion; the fleas actively hunt.
• Godzilla:
  • In The Return of Godzilla, Godzilla is afflicted with 4 to 5ft long sea lice which are hostile to human beings. They are called Shockirus.
  • In Godzilla (2014), the Mutos' life cycle apparently involves multiple larvae infesting a Godzillasaur and pupating inside its body, similar to a Tarantula Hawk and related kinds of wasp. This gives them and Godzilla a pretty good justification for fighting beyond the fact that beating each other senseless while knocking over skyscrapers is just what kaijus do.
• The infamous Carnictis worms from King Kong (2005) originated as internal parasites of large meat-eating dinosaurs, which adapted to survive being excreted from their host and eventually evolved into free-living predators.
• Land of the Lost has a scene where Will Ferrell's character gets a mosquito the size of a football. It drains so much blood out of him he grows pale and passes out, squishing the mosquito.
• In The Lost World (1998), the party's Native Guide dies after being bitten in his sleep by a giant mosquito.

Literature

• In The Kaiju Preservation Society, the Kaiju here are essentially walking ecosystems with the "parasites" actually living on them in an intricate web of commensal and mutual relationships, They're the technically the top predators on the alternate Kaiju Earth doing the actual killing and food collection. Not just between the kaiju and their parasites but between the different species of parasites that live on the Kaiju. There are even a widespread species of parasites solely dedicated to helping the various species of kaiju breathe and cool their biological reactors.
• "Poor Little Warrior" is a short story by Brian Aldiss about a time-traveling big game hunter who kills a brontosaurus (sic), only to be killed by the vermin swarming off its carcass.
• The eponymous Magehunter slays a Giant Crab while docking at Kallamehr's bay. He returns to the same spot, with the crab's carcass still there, only to be attacked by giant parasitic worms feasting on the crab, the size of large snakes.
• The Sky People: Also has dinosaurs, transplants by Sufficiently Advanced Aliens millions of years ago, though on an alternate Venus which have lice the size of crayfish; you do NOT want to get one on you.
• In Star Carrier, a human SEALS (the second "S" stand for "space") team boards a cruiser-sized H'rulka ship, which turns out to be a one-person fighter. They discover that the H'rulka are huge colony organisms, evolved on a gas giant. The creature itself never even notices the SEALS, as they look like ants to it, but the humans almost get attacked by the large parasites living on the alien.

Live-Action TV

• In the Doctor Who episode "Kill the Moon", the characters find the abandoned Mexican mining base on the Moon and discover that the miners were all killed by Big Creepy-Crawlies. However, when the Doctor analyzes them, he concludes that they're not insects at all but merely parasites this large because they are living off the ginormous creature that's about to hatch out of the Moon.

Myths & Religion

• In Hindu Mythology, Earth was made from the remains of a giant which the gods made and sacrificed to themselves. Some versions go on to state that the various parasites on his body became the creatures of the Earth.
• In Norse Mythology, the maggots that fed on the corpse of Ymir, of whom the Earth was made, become Dwarves.

Tabletop Games

• Dungeons & Dragons adventure EX1 Dungeonland. The PCs can encounter a giant dog the size of an elephant. If they search its body (e.g. after killing it) they will discover (and be attacked by) three Giant Ticks.
• Exalted: The gigantic behemoth corpse Juggernaut plays host to enormous carrion maggots, about the size of a cart horse. These are actually of greater use to the Mask of Winters than Juggernaut itself; he plans to breed them to the point where they burst out of the corpse entirely, and then set them on devouring his enemies in the Underworld.
• Pathfinder: Wrackworms are parasites that infest the body of the evil god Rovagug. Given that Rovagug is a horror so large that an entire planetary core had to serve as his cage, wrackworms — while insignificantly small from Rovagug's perspective — are eighty foot-long monsters entirely capable of tearing cities apart, on those occasions when they wriggle out of their host's prison and onto the planet's surface.
• Star Fleet Battles: Captain's Log #40 is a short story titled "The Nature of the Beast". A Federation starship encounters a huge monster called a Space Manta, which is infested with giant parasites. The Manta can "fire" them at targets as if the parasites were guided missiles.

Video Games

• AdventureQuest: Flees and Mytes are ticks and mites the size of the player character and, in their descriptions, are said to come from the furry back of an even bigger Canis Major called a Wild Bingo.
• Bloodborne: Some enemies are infested with parasitic worms that are long enough to become entirely new enemies when the first one is killed. Kos, the dead Eldritch Abomination at the heart of the DLC, has parasites large enough to be equippable hunter weapons.
• Castlevania: Symphony of the Night has Beelzebub, a gigantic corpse hanging from chains which has to be destroyed to stop the giant flies and maggots continually spawning from it.
• Endless Legend has the Urkan Lice, roughly man-sized creatures that infest the Urkans, which are more or-less Kaiju.
• The giant monster Sin from Final Fantasy X is covered in living scales the size of a human called Sinscales, which it can fire in large quantities at small enemies. And that's not even getting into the giant monsters that live inside it.
• Ghouls N Ghosts has a Multi-Mook Melee made up of giant carrion feeders coming out of a giant corpse.
• Kingdom Hearts has the Parasite Cage, boss of the Monstro level. It's significantly larger than Sora.
• The Legend of Zelda:
  • The giant fish Jabu-Jabu from The Legend of Zelda: Ocarina of Time and The Legend of Zelda Oracle of Ages serves as one both games' dungeons, and contains many monsters including a giant Electric Jellyfish.
  • The first boss of The Legend of Zelda: Twilight Princess is a Deku Baba mutated until its mouth can easily swallow you whole, leeching off a particularly gigantic tree.
  • The Legend of Zelda: Skyward Sword's local Space Whale harbors a parasite the size of a building, defeated by throwing its attacks back at it.
• Solatorobo has enemies around your own size found inside the Titano-Machina which are basically its immune system, though there are some ulcer-like parasites.
• Starcraft II: Zerg buildings contain short-lived tiny (relatively speaking, they look about the size of a human) organisms that are little more than teeth, claws, and legs, that swarm the closest enemy unit on the building's death.
• Star Renegades: The Abomination found on Prycon is infested with mites that are roughly the size of the Renegades.
• In Wandering Hamster, Bob the Hamster gets Swallowed Whole by a giant serpent, inside which he will encounter hostile macroscopic cells and bacteria that are about his size. Bob isn't an ordinary little hamster.
• In Warframe, the fish you can catch on Cambion Drift include flagellocanths, which are not so much fish as parasites of the giganic wyrm called Fass who scatters them on the surface of Deimos every time his "sister" Vome regenerates and promptly blows his head up. Flagellocanths can weigh up to 16 kg.
• In World of Warcraft, the planet Azeroth itself is the embryonic form of a Titan called a world soul. The Old Gods are huge parasites that feed on and corrupt dormant world souls.

Western Animation

• In an episode of Catscratch where the cats thaw out a woolly mammoth from a glacier, it comes with fleas big enough for Waffle to ride on like a bucking bronco.
• One episode of Chowder centers around Shnitzel and Chowder climbing a giant to make a delivery, and they run into a swarm of giant bugs along the way. The bugs appearing around waist level and Shniztel's refusal to explain to Chowder where they come from implies the bugs are equivalent to pubic lice.

Real Life

• Whale tapeworms can grow to more than 30 metres long, due to the immense length of their host's digestive tract. Likewise, some of the largest barnacles on Earth grow on the snouts and flukes of humpback whales.
• Dinosaurs and pterosaurs are known to have been infested by giant blood-sucking fleas which were up to an inch in body length, twice the length of the largest living flea species and mammoth compared to common flea species, which are usually only two or three millimetres.

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