Sources
CR
Type
Size
Alignment
Movement

Brontodon

Gargantuan Beast, Unaligned

Armor Class 15 (natural armor)
Hit Points 121 (9d20 + 27)
Speed 30 ft.
STR
21
+5
DEX
9
-1
CON
17
+3
INT
2
-4
WIS
10
+0
CHA
7
-2
Saving Throws CON +6
Senses passive Perception 10
Languages
Challenge 5 (1,800 XP)

Actions

Stomp. Melee Weapon Attack: +8 to hit, reach 20 ft., one target. Hit:27 (5d8 + 5) bludgeoning damage, and the target must succeed on a DC 14 Strength saving throw or be knocked prone.

Tail. Melee Weapon Attack: +8 to hit, reach 20 ft., one target. Hit:32 (6d8 + 5) bludgeoning damage.

Lore

Dinosaurs are the dominant form of animal life in Ixalan—the absolute rulers of the coastal lands held by the Sun Empire, and a force to be reckoned with in the interior jungles. A number of dinosaurs appear in the Monster Manual, with even more to be found in Volo's Guide to Monsters, making that a particularly worthwhile resource for an Ixalan campaign. (Many of the dinosaurs in Volo's Guide also appear in Tomb of Annihilation.)