Buy me a coffee(Dinosaur) Mamenchisaurus — The Colossal Long-Necked Titan of Ancient Forests
Mamenchisaurus: the gigantic long-necked giant that commands the forest canopy—challenge it, and be crushed beneath its massive stride!
Mamenchisaurus is a colossal sauropod distinguished by its extraordinarily long neck, which can reach up to half the length of its entire body. Its massive, pillar-like legs support a bulky, barrel-shaped torso covered in thick, leathery skin. The small head, perched atop the elongated neck, has peg-like teeth designed for stripping leaves from tall trees. Its tail is long and whip-like, providing balance and a defensive weapon.
Behaviour:
Generally docile and slow-moving, Mamenchisaurus spends much of its time grazing on high foliage beyond the reach of most other herbivores. Despite its size, it is surprisingly alert and can react defensively to threats with powerful tail strikes or by trampling. It is a solitary or loosely social animal, sometimes traveling in small herds of juveniles and adults.
Habitat:
Mamenchisaurus inhabits vast, open floodplains and dense forested regions where towering conifers and cycads provide ample food. It favors areas with abundant water sources and plentiful vegetation to sustain its enormous dietary needs.
Modus Operandi:
This giant feeds by using its immense neck to reach treetops without expending energy moving its entire body. When threatened, it relies on intimidation and sheer size, swinging its tail with devastating force or stomping to deter predators. It rarely initiates conflict but will defend itself vigorously if cornered or protecting young.
Motivation:
Driven purely by survival and the instinct to feed, Mamenchisaurus is motivated by the need to consume vast quantities of plant matter daily. Its primary goal is to maintain its strength and protect its territory or offspring from threats. Intelligence is minimal, but its endurance and size make it an awe-inspiring presence in its environment.
Mamenchisaurus 5e
Mamenchisaurus 3.5
Mamenchisaurus
Gargantuan Beast, Unaligned
Armor Class 15 (natural armor)
Hit Points 195 (17d20 + 51)
Speed 40 ft.
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 25 (+7) | 8 (–1) | 17 (+3) | 3 (–4) | 12 (+1) | 7 (–2) |
Saving Throws Str +12, Con +8
Skills Perception +5
Damage Immunities Poison
Condition Immunities Poisoned
Senses Passive Perception 15
Languages —
Challenge 10 (5,900 XP)
Proficiency Bonus +5
Traits
Colossal Reach.
The Mamenchisaurus’s enormous neck and tail allow it to attack creatures up to 15 feet away.
Siege Monster.
The Mamenchisaurus deals double damage to objects and structures.
Trampling Charge.
If the Mamenchisaurus moves at least 20 feet straight toward a creature and hits it with a stomp attack on the same turn, the target must succeed on a DC 18 Strength saving throw or be knocked prone.
Herbivore’s Patience.
Preferring to avoid unnecessary conflict, the Mamenchisaurus will attempt to intimidate or flee before fighting—unless defending territory or young.
Actions
Multiattack.
The Mamenchisaurus makes two attacks: one with its tail and one with its stomp.
Tail Sweep. Melee Weapon Attack: +12 to hit, reach 15 ft., all creatures in a 15-foot cone.
Hit: 27 (4d10 + 7) bludgeoning damage.
Each creature hit must succeed on a DC 18 Strength saving throw or be knocked prone.
Stomp. Melee Weapon Attack: +12 to hit, reach 10 ft., one target.
Hit: 31 (4d12 + 7) bludgeoning damage.
If the target is prone, this attack deals an additional 14 (4d6) damage.
Intimidating Roar (Recharge 5–6).
The Mamenchisaurus unleashes a deafening roar. Each creature of its choice within 60 feet that can hear it must succeed on a DC 16 Wisdom saving throw or be frightened for 1 minute. A frightened creature can repeat the saving throw at the end of each of its turns, ending the effect on a success.
Tactics
- Defensive Giant: Uses its roar and size to discourage foes before engaging.
- Area Control: Uses Tail Sweep to knock down groups and control space.
- Focused Assault: Targets vulnerable foes with Stomp, especially prone enemies.
- Territorial: Defends territory and young fiercely, but retreats if badly injured.
Legendary Actions
The Mamenchisaurus can take 2 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. It regains spent legendary actions at the start of its turn.
- Tail Swipe. The Mamenchisaurus makes one Tail Sweep attack.
- Step. The Mamenchisaurus moves up to half its speed without provoking opportunity attacks.
Mamenchisaurus
This massive quadruped has a long tail, a box-like head attached to a disproportionately long neck, and a wrinkled, elephantine hide.
Originally Posted by Shade of the En World forums.
On this Thread
Although mamenchisaurs are not the longest, heaviest or otherwise record-setting dimensionally of the massive sauropods, they do have the longest necks of their family. The neck of a mamenchisaurus takes up almost 40 feet of its 70 foot length and is held at a slightly erect angle. Due to the massive pressures needed to pump blood up to its head, multiple heart-like structures are positioned along its neck. Mamenchisaurs are at a significant advantage when it comes to a wide field of vision and a selection of food from the tallest of trees, but their lives are among the shortest of the sauropods (only seventy-five years at a maximum, barring a violent end) due to their fragile hearts.
| Dinosaur, Mamenchisaurus | |
| Colossal animal | |
| Hit Dice | 22d8+181 (277 hp) |
| Initiative | +1 |
| Speed | 30 ft. (6 squares) |
| Armor Class | 12 (-8 size, +1 Dexterity, +9 natural), touch 3, flat-footed 11 |
| Base Attack/Grapple | +16/+42 |
| Attack | Tail slam +18 melee (4d6+15 plus thunderous snap) |
| Full Attack | Tail slam +18 melee (4d6+15 plus thunderous snap) |
| Space/Reach | 50 ft./40 ft. |
| Special Attacks | Thunderous snap, trample 8d8+15 |
| Special Qualities | Low-Light Vision, Scent |
| Saves | Fort +22, Ref +16, Will +11 |
| Abilities | Strength 30, Dexterity 12, Constitution 25, Intelligence 1, Wisdom 14, Charisma 10 |
| Skills | Listen +12, Spot +21 |
| Feats | Alertness, Diehard, Endurance, Epic Toughness, Great Fortitude, Iron Will, lightning reflexes, Power Attack |
| Environment | Warm forests, plains and hills |
| Organization | Solitary, pair or herd (10-24) |
| Challenge Rating | 10 |
| Treasure | None |
| Alignment | Always neutral |
| Advancement | 23-66 HD (Colossal) |
| Level Advancement | – |
COMBAT
Although they are more closely related to camarasaurs and brachiosaurs than diplodocids, they bear the latter’s whip-like tail, complete with its sonic consequences. More often then not, however, they merely trod on any threat to their safety.
Thunderous Snap (Ex): Although they are ponderous, a mamenchisaurus’ whip-like tail can move faster than sound. Any creature struck by a mamenchisaurus’ tail slam must make a Fortitude save (DC 28) 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): A mamenchisaurus can literally run over any creatures in its way that are of Gargantuan or smaller size. Creatures trampled must make a Reflex save (DC 31 half) or take 8d8+15 damage. The save DC is Strength-based.
Originally appeared in Monstrous Compendium Volume Three: Forgotten Realms Appendix (1989).