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Dinosaur, Plesiosaurus

Plesiosaurus dolichodeirus 2008

Strongly aggressive, attacking anything it notices. It’s neck is about one-third of its total length

Originally Posted by Boz of the En World forums.

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This beast has a thick, ovoid body with fins instead of legs and a long, snaky neck and tail. The neck takes up about one third of the creature’s total length.

The plesiosaurus is a relative of the aquatic carnivore, elasmosaurus. The elasmosaurus is longer overall, but its neck makes up a larger percentage of its total length, compared to the plesiosaurus.

A plesiosaurus is usually around 20 feet in length from nose to tail, and much of this is neck and tail. They weigh about 3000 pounds and are more aggressive than their larger relatives. Although they eat fish almost exclusively, other large moving objects in their territory, like ships, easily disturb them.

Dinosaur, Plesiosaurus
Huge animal
Hit Dice15d8+78 (145 hp)
Speed20 ft (4 squares), Swim 50 ft
Armor Class13 (-2 size, +2 Dexterity, +3 natural), touch 10, flat-footed 11
Base Attack/Grapple+11/+25
AttackBite +15 melee (2d6+9)
Full AttackBite +15 melee (2d6+9)
Space/Reach15 ft/10 ft (15 ft with bite)
Special Attacks
Special QualitiesHold breath, Low-Light VisionScent
SavesFort +14, Ref +11, Will +6
AbilitiesStrength 23, Dexterity 15, Constitution 20, Intelligence 2, Wisdom 13, Charisma 7
SkillsHide +6*, Listen +6, Spot +6, Swim +14
FeatsAlertnessCombat ReflexesDiehardEndurancePower AttackToughness
EnvironmentWarm aquatic
OrganizationSolitary, pair or herd (3-12)
Challenge Rating8
AlignmentAlways neutral
Advancement16-30 HD (Huge), 31-45 HD (Gargantuan)
Level Adjustment


Plesiosaurs attack exclusively with their powerful bites. They favor ambush tactics when hunting and many lookouts don’t know they’re in plesiosaur territory until it’s too late. These aggressive beasts are strong and fast, and likely to lunge at anything that moves.

Hold Breath (Ex): A plesiosaurus can hold its breath for a number of rounds equal to 8 times its Constitution score before it risks drowning.

Skills: Plesiosaurs receive a +8 racial bonus on Hide checks made underwater.

A plesiosaurus has a +8 racial bonus on any Swim check to perform a special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered. It can use the run action while swimming, provided it swims in a straight line.

Originally found in the first edition Monster Manual (1977, Gary Gygax), Monstrous Compendium MC3 – Forgotten Realms Appendix I (1989), and Monstrous Compendium Annual Two (1995). It also appeared in the original D&D module X1 – The Isle of Dread (1981, David Cook and Tom Moldvay).

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