Large fiend, chaotic evil

Armor Class 15 (natural armor)
Hit Points 142 (15d10 + 60)
Speed 40 ft., climb 40 ft., swim 40 ft.

25 (+7) 16 (+3) 18 (+4) 7 (-2) 14 (+2) 12 (+1)

Saving Throws Con +7
Skills Perception +5, Stealth +6
Damage Resistances psychic
Damage Immunities acid, poison
Condition Immunities poisoned
Senses darkvision 60 ft., passive Perception 15
Languages Abyssal, Common, Draconic
Challenge 8 (3,900 XP)


  • Innate Spellcasting. The guariba-boia’s spellcasting ability is Wisdom (spell save DC 12). The guariba-boia can innately cast the following spells, requiring no material components:
  • Keen Sight. The guariba-boia has advantage on Wisdom (Perception) checks that rely on sight.
  • Whooping Howl. The guariba-boia produces a whooping howl to which fiends and monstrosities are immune. Any other creature that starts its turn within 30 feet of the guariba-boia must make a DC 13 Constitution saving throw, taking 3d10 psychic damage on a failed save, or half as much damage on a successful one. A creature that can’t hear the howl automatically succeeds on the save.


  • Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 12 (1d8 +7) piercing damage and the target must make a DC 15 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much damage on a successful one. Additionally, if the creature fails the Constitution saving throw with a total of 5 or less they are instantly paralyzed for 1 minute. At the end of each of the creature’s turns, they can make a Constitution saving throw. On a success, the condition ends.
  • Constrict. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage, and the target is grappled (escape DC 18). Until this grapple ends, the creature is restrained, and the guariba-boia has disadvantage on attack rolls to constrict another target. If it has one Large or two Medium or smaller creatures constricted, it can’t constrict another target.
  • Swallow. The guariba-boia makes one bite attack against a Large or smaller target it is grappling. If the attack hits, the target is swallowed, and the grapple ends. The swallowed target is blinded and restrained, it has total cover against attacks and other effects outside the guariba-boia, and takes 13 (3d8) acid damage at the start of each of the guariba-boia’s turns. The guariba-boia can have only one Large creature or up to 2 Medium or smaller creatures swallowed at a time. If the guariba-boia dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 5 feet of movement, exiting prone if on land.


This large golden-scaled snake has the head of a shrieking howler monkey with long, flowing golden fur. A pair of short arms with webbed fingers aid it in swimming in its home rivers and also in burrowing out undercuts beneath the banks where it lies in wait for unsuspecting prey to approach. They unleash thunderous roars from beneath the waters, drawing the curious near, and their calls echo throughout the jungle on rainy nights. Their fangs are needle-sharp and envenomed, with even a small bite leading to agonizing death. They are equally satisfied with consuming animals as humanoids, but sometimes overturn canoes and tear their occupants apart when hungry or simply feeling malicious.

Fiendish Hybrid. The first guariba-boias came into the world as demonic monkey familiars to tribal shamans and warlocks, but upon the death of their masters ordinary jungle snakes sought to consume them to still their squalling cries. Infused with the fiendish powers of the nether regions, these demon-monkeys savagely clawed apart their attackers even as they were being devoured, but their eldritch savagery merged them into a new and monstrous form of life that merged the two into a hideous blend of mammal and reptile. Instilled with fiendish power, the guariba-boias have spread throughout the jungles, somehow propagating themselves through collecting the bones of their victims and weaving them together in strange rituals into more fiendish horrors like themselves.

Section 15: Copyright Notice

Latin American Monsters (5E) © 2021, Legendary Games; Authors Miguel Colon, Ismael Alvarez, Robert J. Grady, Jason Nelson.

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