I hope you enjoy the amorphosaurus rex, and I'll be back next time with a new monster. Thanks for reading!
This smallish, green-skinned tyrannosaurus extrudes a pair of tentacles from its back.
Amorphosaurus Rex CR 14
CN Huge aberration
Init –2; Senses darkvision 60 ft.; Perception +11
AC 30, touch 6, flat-footed 30 (–2 Dex, +24 natural, –2 size)
hp 210 (20d8+120); fast healing 2
Fort +12, Ref +4, Will +12
Defensive Abilities adaptive resistance, amorphous; DR 10/cold iron; Immune acid, polymorph; Resist cold 5, electricity 5, fire 5
Speed 50 ft., swim 80 ft.
Melee bite +23 (4d6+15/19–20 plus grab), 2 tentacles +22 (2d8+5)
Space 15 ft.; Reach 15 ft.
Special Attacks constrict (2d8+10), swallow whole (2d8+10, AC 22, 21 hp)
Str 31, Dex 6, Con 22, Int 5, Wis 10, Cha 10
Base Atk +15; CMB +27 (+29 bull rush and overrun, +31, +29 overrun); CMD 35 (37 vs. bull rush and overrun)
Feats Awesome Blow, Dazzling Display, Diehard, Endurance, Improved Bull Rush, Improved Critical (bite), Improved Overrun, Multiattack, Power Attack, Weapon Focus (tentacle)
Skills Intimidate +15, Perception +11, Swim +18
Organization solitary or pair
Adaptive Resistance (Su) When an amorphosaurus rex takes energy damage greater than its current resistance, the value increases by 5 for subsequent energy damage (for example, if a spell deals 7 points of fire damage, it takes 2 points of damage, and then its resist fire increases to 10). This increased resistance lasts for an hour after it takes damage.
Related to chaos beasts and gibbering mouthers, proto-amorphosaurus rexes had a similarly unstable form. Unlike those creatures, the amorphosaurus rexes instinctively locked in on the alpha predator at the time and their outward appearance permanently changed. However, they retained rudimentary shapeshifting abilities, allowing them to generate decidedly non-dinosaur features, with octopus tentacles as their weapons of choice. Their internal organs constantly shift, making it impossible to harm them by damaging an internal organ. Their weird biology allows them to heal wounds rapidly as well. Finally, they have a modicum of protection from elemental damage, and this protection increases as they are exposed to it.
While the tyrannosaurus rex is the typical form taken by amorphosaurus rexes, variants include sharks and bears. Regardless of the shape they “fix” on, they always have an incongruous feature (tentacles, whip-like tails, fanged mouths within mouths, etc.) that mark them out as unnatural.