In the vast world of Dungeons & Dragons, there are a plethora of monsters that Dungeon Masters love to throw at players. As a core part of the Dungeons & Dragons experience, monsters need to have variety in looks, locales, and especially in their abilities. Monsters come in all shapes and sizes, scaling from the tiniest of beings to the most monstrous and colossal of creatures.

Out of all the sizes of monsters, there is a sort of fear that comes with gargantuan monsters. These monsters take up at least a 20ft by 20ft square and have the potential to be even larger than that. From the mightiest Tarrasque to the sea-dwelling krakens, these monsters will have players running to the hills and wishing that they had stayed home from their adventures.

10 Dinosaurs: Jurassic Park Got a Lot Worse

Dinosaurs have always been a part of 5th Edition with the inclusion of the prehistoric reptiles in the Monster Manual back in 2014. However, in 2024 with the release of Bigby Presents: Glory of the Giants, new types of dinosaurs were introduced. These four dinosaurs are classified as gargantuan monstrosities instead of beasts. The book presents the four different dinos: the ceratops, the altisaur, the aerosaur, and the regisaur.

Starting with the ceratops, this is the triceratops-coded monstrosity. With magic resistance, a powerful multiattack, and a CR of 9, the ceratops is a threat to any lower level party. The altisaur is the brachiosaurus-coded dino. This sauropod is a walking mountain with six legs, and a massive tail attack. The altisaur is the pteranodon-coded dinosaur that boosts a powerful wind gust attack. Finally, the regisaur is the Tyrannosaurus-coded giant dino. This beast can swallow party members as a bonus action and is the strongest of the four types.

9 Arachnophobia Just Got Real: The Citadel Spider

Spiders have been a classic beast in Dungeons & Dragons since the game's founding. Between swarms of spiders and even giant spiders, these arachnids have always skittered their place into adventures of all kinds. However, a new adventure has given a whole new meaning of fear to the spider.

Introduced in the recent Vecna: Eve of Ruin adventure, the Citadel Spider is a force to be reckoned with. On its own, the monstrosity has a powerful web bomb attack, in addition to the regular traits of spiders such as Spider Climb and Web Walker. The Citadel Spiders also come with Legendary Resistances, condition immunities, and the Absorb Blow reaction. This horrible creation of Lolth's followers can be the bane to any unsuspecting party.

8 The Roc Equals Big Bad Bird

Straight out of Middle Eastern mythology, the Roc is a great classic foe for any adventuring party. These massive birds of prey might not be the most deadly of creatures, but they certainly can cause a lot of damage with their multiattacks and tanky health block. What seems to be a normal bird can quickly become a nightmare as the Roc is basically a gargantuan bird of prey.

Luckily for parties facing this terrible beast, Rocs are solitary creatures. They are rarely found in groups, yet their Keen Sight ability will allow them to snuff out prey hidden on the ground below. Found in a wide variety of environments, the Roc could be a great addition to any Dungeon Master's menagerie of creatures.

7 The Purple Worm is the Terror From Beneath

A Dungeons & Dragons classic, the Purple Worm is a great creature to cause a party to quake in their boots. Burrowing beneath the ground, the Purple Worm can easily take any party traveling in a desert or the Underdark by surprise. The Purple Worm is made more dangerous thanks to its Tremorsense ability, allowing it to pinpoint vibrations caused by movement.

If being able to swallow players whole wasn't enough, the Purple Worm also has a powerful tail stinger that will cause a ton (12d6s worth) of poison damage. Worse than that, players will need to get past the Worm's chitinous AC of 18 to even take out a small chunk of this creature's bountiful health.

6 Krakens are True Legends of the Deep

Sailors and pirates are right to be fearful of the dreaded Kraken. If a party finds one of these leviathans while sailing the high seas, it may be best to abandon course. The Kraken is one of the most feared creatures in 5e, with a massive health pool and a CR of 23. The physicality of these creatures is so great that they deal double damage to structures thanks to their Siege Monster trait.

Krakens have a host of abilities that make them so deadly. Lightning storms, tentacle attacks, and ink clouds from the Kraken are the least of the party's worries. The Kraken also makes use of powerful Lair Actions and Regional Effects that change the tide of battle. They can charge the water with electricity, cause strong currents, alter weather, and even charm lesser aquatic animals to do their bidding.

5 Huge Wasn't Big Enough For Giant Scions

Giants have been one of the more elusive creatures in 5e lore with not much written about them. However, all of this changed with the release of Bigby Presents: Glory of the Giants. With a ton of new lore, this book introduced new types of Giants. The most fearsome of the Giants from this book were the Scions of the Giant gods.

The sheer power of the Scions empowers all giants of the Scion's type within 1000 feet, giving them a +7 to attack and damage rolls. Beyond that, these Scions have a monolithic health pool, environment-altering Regional Effects, tons of immunities and resistances, and Giant-sized attacks, making them some of the most powerful creatures in 5e history.

4 The Neothelid is An Eldritch Abomination

Slithering through the Underdark, the Neothelid is the result of the Mind Flayer cycle gone rogue. Born from the collapse of a Mind Flayer colony, the Neothelid is a tentacled horror that'll make for a great fight when the players least expect it. Feared even by Mind Flayers themselves, the Neothelid boasts a plethora of powerful abilities.

The Neothelid is drawn to a creature's Intelligence score, being able to sense any creature with a score of 4 or higher within one mile due to its Creature Sense trait. Its tentacles can be used to trap and eat creatures, and the Neolithid can use an acidic breath attack as well as cast a few powerful psionic spells.

3 Cradle Elementals Are Shells For the Scion Giants

As Bigby Presents: Glory of the Giants introduced the Scions of the Giant gods, the book also introduced the Cradles of the Scions. These are elemental resting grounds for each of the Scions. Creatures in their own right, the Cradles are literal forces of nature that will protect the resting Scion until the elementals die, on which the Scion is instantly released and awoken. Therefore, parties should be ready for a double fight when finding a Cradle.

Cradles have very similar abilities to their respective Giant Scion. Additionally, some Cradles rip open portals to the Elemental Planes, letting elemental creatures pour into the Material Plane. Other Cradles have powerful Regional Effects that can cause crops to grow, animals to thrive, or even compel creatures to leave offerings for the Cradle.

2 The Tarrasque is the Original Dungeons & Dragons Titan

The name of the legendary Tarrasque has been whispered throughout the years of Dungeons & Dragons. Players seem to always know the name of this creature, but few have encountered the creature. Being on the same scale as the Dragon Queen, Tiamat, with a CR 30 statblock, the Tarrasque is an unstoppable force. Ranged attack spells have a chance to be reflected off of the beast's carapace, and it can make five attacks after using its Frightful Presence ability.

Feared throughout the Material Plane as the greatest monster to exist, the Tarrasque certainly lives up to the name. On top of everything, the Tarrasque can make use of powerful legendary actions to move across the battlefield, attack, or even swallow a creature whole. The last thing any party wants to hear is that they have stumbled across a Tarrasque.

1 Ancient Dragons Are Iconic But Deadly

Arguably the most iconic monster in all fantasy, there is nothing more heart-provoking, terrifying, and epic than fighting a dragon. In Dungeons & Dragons, dragons come in different sizes and types. The gargantuan-scale dragons in the Monster Manual are known as Ancient Dragons. With being in the title of the game, these creatures have a host of powerful abilities.

Pulling no punches, the Ancient Dragons have strong attacks, options for 6 Regional Effects and Lair Actions, each of which changes per type of dragon, Legendary Actions, and lethal breath attacks. To make matters worse for the party, the Ancient Dragons have the option to be powerful spellcasters, with a host of insanely deadly spells at their disposal.