Huge beast, unaligned

Armor Class: 13

Hit Points: 150 (14d12+66) 14d12+66

Speed: 30 ft , swim: 50 ft

STR

22 +6

DEX

9 -1

CON

18 +4

INT

2 -4

WIS

12 +1

CHA

9 -1

Skills: Perception +2;

Senses: passive Perception 14

Languages: —

Challenge Rating: 6

by Mario Lanzas

Actions

Multiattack: The Spinosaurus makes two attacks: one with their bite and one with their tail.   Bite: Melee Weapon Attack: +9 to hit, reach 5 ft., one target.
Hit: 24 (3d10+6) 3d10+6 piercing damage, and the target is grappled (escape DC 16). Until the grapple ends the target is restrained and the Spinosaurus cannot bite another creature.   Death Roll: The Spinosaurus rolls its body while grappling a creature, causing immense amounts of pain and damage. The Spinosaurus must have grappled a creature with its Bite and be at least partially submerged in liquid up to 5 ft. deep. Upon using the Death Roll action, the Spinosaurus inflicts 2d8 2d8 bludgeoning damage and the creature must make a DC 16 Constitution saving throw or lose 1 minute of breath. If the creature drops beneath their breathing threshold (see pp. 183 of the Player's Handbook), they begin to drown.   Tail: Melee Weapon Attack: +9 to hit, reach 10 ft. one target not grappled by the Spinosaurus.
Hit: 20 (3d8+6) 3d8+6 bludgeoning damage. If the target is a creature, it must succeed on a DC 16 Strength saving throw or be knocked prone.

Suggested Environments

Spinosaurus lived in marshy river deltas and coastal wetlands, taking advantage of their terrestrial and aquatic movement to travel from bayou to bayou in search of food. They prefer to hunt from the shore, striking prey like an egret. However, their powerful, rudder-like tails do allow them a great deal of mobility and speed in the water, though their pursuit is often obstructed by the tree roots and shallow waterways found in their environments.