Buy me a coffeeDinosaur, Eustreptospondylus
“Stranded on ancient shores and hungry for flesh, this island-hopping killer turns isolation into extinction—meet Eustreptospondylus, the Jurassic’s deadliest castaway.”
Large Beast, Unaligned
Appearance
Eustreptospondylus is a lean, muscular predator with a long, narrow skull lined with jagged, blade-like teeth. Its dark, mottled skin—often a blend of earthen grays, algae green, or brackish brown—helps it blend into the dense ferns and tidal rock formations of its coastal haunts. Powerful hind limbs end in taloned feet suited for gripping wet stone, while shorter but strong forelimbs bear sharp, three-fingered claws. Its stiff, tapering tail acts as a counterbalance, allowing sudden bursts of speed or dynamic shifts in balance while navigating unstable ground.
Behaviour
Clever and opportunistic, Eustreptospondylus is a solitary hunter that uses stealth, speed, and terrain knowledge to trap or outmaneuver prey. It shows a disturbing patience—often following wounded creatures or watching campsites from the shadows before closing in. Its eyes reflect dim light with a low, coppery gleam, hinting at excellent night vision and predatory focus. It rarely roars or bellows, preferring a low growl or click-like vocalization used to warn off rivals or communicate with mates during the breeding season.
Habitat
Native to storm-swept coastlines, tidal flats, and island interiors, Eustreptospondylus is often encountered near brackish swamps, estuaries, or even shallow marine shelves. Fossilized ancestors were found in marine deposits, suggesting it may swim short distances between islets. In fantasy settings, they may be found in lost island chains, ancient coral ruins, or as mutated guardians of druidic coastal relics.
Modus Operandi
Eustreptospondylus prefers ambush tactics—lurking among shoreline boulders or tall salt reeds before lunging with terrifying precision. If facing multiple enemies, it will single out the smallest or weakest and attempt to isolate them, using chase-and-pull maneuvers to split prey. It strikes fast and retreats just as quickly, luring foes into deeper water or unstable terrain before finishing the kill. It is highly territorial and may stalk invaders for hours before engaging.
Motivation
Driven primarily by hunger and instinct, Eustreptospondylus operates on a razor edge of caution and ferocity. It is not needlessly aggressive, but once it commits to the hunt, it becomes relentless. In rare cases, they have been observed hoarding carrion or nesting near magical leylines, suggesting subtle attunements to arcane environments or signs of unnatural intelligence in more evolved specimens.
Eustreptospondylus 5e
Eustreptospondylus 3.5
Eustreptospondylus
Large Beast, Unaligned
Armor Class 14 (natural armor)
Hit Points 85 (10d10 + 30)
Speed 40 ft., swim 20 ft.
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 19 (+4) | 14 (+2) | 16 (+3) | 2 (−4) | 12 (+1) | 7 (−2) |
Saving Throws Dexterity +4, Wisdom +3
Skills Perception +3, Stealth +4
Senses Passive Perception 13
Languages —
Challenge 4 (1,100 XP)
Proficiency Bonus +2
Traits
Keen Smell.
The Eustreptospondylus has advantage on Wisdom (Perception) checks that rely on smell.
Amphibious Hunter.
While not capable of breathing underwater, the Eustreptospondylus can hold its breath for up to 15 minutes and has a swim speed of 20 feet, allowing it to traverse short aquatic distances between islands or across rivers.
Pounce.
If the Eustreptospondylus moves at least 20 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 14 Strength saving throw or be knocked prone. If the target is prone, the Eustreptospondylus can make one bite attack against it as a bonus action.
Actions
Multiattack.
The Eustreptospondylus makes two attacks: one with its bite and one with its claws.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target.
Hit: 18 (2d10 + 4) piercing damage.
Claw. Melee Weapon Attack: +6 to hit, reach 5 ft., one target.
Hit: 14 (2d8 + 4) slashing damage.
Description
Eustreptospondylus is a robust, bipedal theropod dinosaur, measuring approximately 6 to 7 meters (20 to 23 feet) in length and weighing between 500 to 600 kilograms (1,100 to 1,300 pounds). Its elongated skull houses sharp, serrated teeth, ideal for slicing through flesh. The dinosaur’s powerful hind limbs support swift movement, while its relatively short forelimbs end in three-fingered hands equipped with curved claws. A long, stiff tail provides balance during locomotion.
This solitary predator exhibits opportunistic hunting strategies, often stalking prey along the coastal regions of Middle Jurassic Europe. Its keen senses and agility make it an effective ambush hunter, capable of sudden bursts of speed to capture unsuspecting prey. Fossil evidence suggests it may have scavenged as well, feeding on carcasses washed ashore.
Eustreptospondylus inhabited the scattered islands of what is now southern England during the Middle Jurassic period, approximately 165 million years ago. The region’s marine deposits, where its fossils were discovered, indicate a coastal or island environment, supporting theories of its shoreline hunting and possible swimming capabilities between islands.
A scarred grey head bobs up and down in the waves. You run for cover in the jungle as the predator scrambles on land and lies down to relax. You know that it is tired, but it could still probably crush you to death in those powerful jaws. The creature lies out in the sun, drying itself and trying to pick up the scent on carrion nearby.
Originally Posted by Darknecromancer of the Wizards Community forums.
On this Thread
Eustreptospondylus is one of the most adaptable of predators. It has developed as both an active hunter and a scavenger to help it survive. It has also learned how to swim and island hop to keep its stomach full. They appear much as a miniature allosaur, but have a shorter head compared to the larger predator.
| Eustreptospondylus | |
| Large animal | |
| Hit Dice | 8d8 +16 (52 hp) |
| Initiative | +3 (+3 Dexterity) |
| Speed | 30 feet (8 squares), Swim 20 ft |
| Armor Class | 16 (+5 natural, +2 Dexterity, -1 Size) , Touch 11, Flat Footed 14 |
| Base Attack | +6 |
| Attack | Bite +9 melee (1d8+3) |
| Full Attack | Bite +9 melee (1d8 +2), 2 Claws +2 melee (1d4 +1) |
| Space/Reach | 5 ft/ 5 ft |
| Special Attacks | |
| Special Qualities | Low Light Vision, Scent, Cast-Iron Stomach |
| Saves | Fort +8, Ref +8, Will +4 |
| Abilities | Strength 15, Dexterity 14, Constitution 15, Intelligence 2, Wisdom 14, Charisma 6 |
| Skills | Hide +11, Listen +13, Spot +12, Swim +15 |
| Feats | Weapon Focus (Bite), Multiattack, |
| Environment | Warm Forests |
| Organization | Solitary or Pair |
| Challenge rating | 7 |
| Treasure | none |
| Alignment | Always Neutral |
| Advancement | 9-15 HD (Large) 16-25 (Huge) |
Combat
A Eustreptospondylus will attack anything smaller than it, and is more than willing to chase of other predators to get a good meal. If the meal is large enough, as many as 9 adult Eustreptospondyluses can tolerate each other’s presences, but leave or chase each other off as soon as food sources dwindle.
Cast-Iron Stomach (Ex) much like common vultures, a Eustreptospondylus will eat anything and gain a +3 bonus on Fortitude saves dealing with natural diseases, but not supernatural diseases such as mummy rot.