(Dinosaur) Argentinosaurus, the Colossal Titan
“Argentinosaurus towers over the ancient landscape, an unstoppable giant that dominates all in its path!”
Argentinosaurus is a colossal sauropod dwarfing the tallest trees around it. Its massive, elongated neck stretches high into the sky, ending in a small, narrow head with blunt teeth for stripping foliage. Its thick, pillar-like legs support a bulk so immense it causes the ground to tremble with every step. A long, heavy tail sweeps behind, balancing its immense frame and capable of powerful strikes.
Behaviour:
Generally slow and deliberate, Argentinosaurus moves with surprising grace despite its size. It is a gentle giant, focused on foraging vast amounts of plant matter. When threatened, it uses its tremendous size and tail to defend itself, delivering devastating blows to any predator foolish enough to approach.
Habitat:
Argentinosaurus roams expansive floodplains and dense prehistoric forests, where tall conifers and cycads provide abundant food. It favors areas with open space to accommodate its immense size and avoid becoming trapped or cornered.
Modus Operandi:
This titan forages continuously, browsing high into the treetops or grazing on low-lying vegetation. Its massive bulk is both defense and deterrent—predators rarely challenge it unless desperate. When threatened, Argentinosaurus swings its tail with incredible force, creating shockwaves that can topple attackers.
Motivation:
Survival and sustenance dominate its existence. Argentinosaurus moves slowly but deliberately to maintain access to abundant food and safe ground. Its primary motivation is to live unmolested, using size and power to ward off danger, ensuring longevity and the ability to reproduce.
Argentinosaurus 5e
Argentinosaurus 3.5
Argentinosaurus, the Colossal Titan
Gargantuan Beast, Unaligned
Challenge 15 (13,000 XP)
Armor Class 18 (natural armor)
Hit Points 310 (23d20 + 115)
Speed 40 ft.
STR | DEX | CON | INT | WIS | CHA |
---|---|---|---|---|---|
30 (+10) | 8 (–1) | 20 (+5) | 2 (–4) | 12 (+1) | 8 (–1) |
Saving Throws: Con +11, Wis +7
Skills: Perception +7
Damage Immunities: Psychic
Condition Immunities: Charmed, Frightened, Paralyzed, Petrified
Senses: Passive Perception 17
Languages: —
Challenge: 15 (13,000 XP)
Traits
Titanic Presence.
Creatures of Large size or smaller must succeed on a DC 18 Wisdom saving throw or become Frightened for 1 minute if they start their turn within 30 feet of Argentinosaurus. Creatures can repeat the saving throw at the end of each of their turns.
Siege Monster.
It deals double damage to objects and structures.
Slow but Unstoppable.
Despite its colossal size, Argentinosaurus ignores difficult terrain caused by plants and uneven ground.
Actions
Multiattack.
It makes two attacks: one with its Tail Sweep and one with its Stomp.
Tail Sweep.
Melee Weapon Attack: +16 to hit, reach 20 ft., all creatures in a 20-foot cone.
Hit: 28 (4d10 + 10) bludgeoning damage.
Special: Creatures hit must succeed on a DC 22 Strength saving throw or be knocked prone.
Stomp.
Melee Weapon Attack: +16 to hit, reach 10 ft., one target.
Hit: 36 (6d6 + 10) bludgeoning damage, and the target must succeed on a DC 22 Dexterity saving throw or be stunned until the end of its next turn.
Legendary Actions
Argentinosaurus can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature’s turn.
- Stomp. Argentinosaurus makes a foot attack against one creature within 10 feet.
Attack: +16 to hit, 36 (6d6 + 10) bludgeoning damage, and the target must succeed on a DC 22 Dexterity saving throw or be stunned until the end of its next turn. - Earthshaking Roar (Costs 2 Actions). Argentinosaurus emits a terrifying roar. Each creature within 60 feet must make a DC 18 Constitution saving throw or be deafened and Frightened for 1 minute. Affected creatures can repeat the save at the end of each of their turns.
Legendary Resistance (3/Day)
If Argentinosaurus fails a saving throw, it can choose to succeed instead.
Tactics
- Uses Tail Sweep to knock down groups of foes and keep them at bay.
- Uses Stomp to target and disable dangerous enemies.
- Employs Earthshaking Roar to scatter attackers and disrupt coordinated assaults.
- Relies on Titanic Presence to intimidate and control the battlefield.
- Maneuvers freely despite terrain thanks to Slow but Unstoppable.
Argentinosaurus

Argentinosaurus is a herbivorous sauropod dinosaur genus that was quite possibly the largest, heaviest land animal that ever lived.
Insane Pixie of the Wizards Community forums.
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It developed on the island continent of South America during the middle of the Cretaceous Period (around 100 million years ago), after all of its more familiar Laurasian Jurassic kin – like Apatosaurus – had long disappeared.
Argentinosaurus’ measure between 115 to 150 feet long, stand about 50 feet tall, and weigh about 80 tons.
Argentinosaurus | |
Colossal animal | |
Hit Dice | 32d8+323 (467 hp) |
Initiative | +0 |
Speed | 30 ft. (6 squares) |
Armor Class | 22 (-8 size, +20 natural), touch 2, flat-footed 22 |
Base Attack/Grapple | +24/+57 |
Attack | Tail slam +23 melee (4d6+25 plus thunderous snap) or stamp (10d8+25) |
Full Attack | Tail slam +23 melee (4d6+25 plus thunderous snap) or stamp (10d8+25) |
Space/Reach | 80 ft./40 ft. |
Special Attacks | Thunderous snap, trample 8d8+25 |
Special Qualities | Low-Light Vision, Scent |
Saves | Fort +33, Ref +10, Will +12 |
Abilities | Strength 44, Dexterity 10, Constitution 30, Intelligence 1, Wisdom 14, Charisma 10 |
Skills | Listen +23, Spot +22 |
Feats | Alertness, Awesome Blow, Diehard, Endurance, Great Fortitude, Improved Bull Rush, Power Attack, Toughness |
Climate/Terrain | Warm forests, plains and hills |
Organization | Solitary |
Challenge Rating | 17 |
Treasure | None |
Alignment | Always neutral |
Advancement | 33-78 HD (Colossal) |
Level Adjustment | – |
Combat
Thunderous Snap (Ex): Although an argentinosaurus is ponderous, its whip-like tail can move faster than sound. Any creature struck by an argentinosaurus’ tail slam must make a Fortitude save (DC 36) or be stunned for 1d4 rounds and deafened for 1d4 minutes. On a successful save, the creature is merely deafened for 1d4 minutes. The save DC is Constitution based.
Trample (Ex): An argentinosaurus can literally run over any creatures in its way that are of Gargantuan or smaller size. Creatures trampled must make a Reflex save (DC 43 half) or take 8d8+25 damage. The save DC is Strength-based.