Creature Reference Back to Creatures

Sea Serpent

Gargantuan · Monstrosity · CR 16 · Chaotic Evil

Source. Monstrous Menagerie

247 (15d20+90)

Ability Scores

Core attributes and their modifiers.

STR

DEX

CON

INT

-3

WIS

CHA

-1

Overview

Category Monsters

Size Gargantuan

Type Monstrosity

Alignment Chaotic Evil

XP 15000

Initiative Bonus +0

Movement

Walk 10 ft (3 m)

Swim 50 ft (15.2 m)

Climb 5 ft (1.5 m)

Crawl 5 ft (1.5 m)

Senses

Darkvision 60 ft (18.3 m)

Passive Perception 12

Saving Throws

Dexterity +5 Constitution +11 Intelligence +2 Wisdom +7 Charisma +4

Traits

Amphibious

The serpent can breathe air and water.

Reactive

The serpent can take two reactions per round, one with its tail and one with its bite. It can't take two reactions on the same turn.

Sinuous

The serpent can share the space of other creatures and objects.

Actions

Bite

+14 to hit, reach 15 ft (4.6 m). Hit: 4d10+9 piercing damage.

Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 31 (4d10 + 9) piercing damage.

Coils

+14 to hit, reach 5 ft (1.5 m). Hit: 4d20+9 bludgeoning damage.

Melee Weapon Attack: +14 to hit, reach 5 ft., one Large or larger target in its space. Hit: 51 (4d20 + 9) bludgeoning damage. If the target is a creature it is grappled (escape DC 22). If the target is an object it is held. Until the grapple or hold ends the targets speed is reduced to 0 and the sea serpents coils attack automatically hits the target. If an attacker subjects the serpent to a critical hit this grapple or hold ends.

Recover

1/day

The serpent ends one condition or effect on itself.

Tail

+14 to hit, reach 15 ft (4.6 m). Hit: 4d8+9 bludgeoning damage.

Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 27 (4d8 + 9) bludgeoning damage. If the target is a creature it makes a DC 22 Strength saving throw. On a failure it is pushed up to 15 feet away from the serpent and knocked prone.

Thrash (While Bloodied)

The serpent moves up to its speed and then attacks with its tail and its bite.

Reactions

Reactive Bite

If the serpent takes 15 damage or more from a melee attack made by a creature it can see, it bites the attacker.

Reactive Tail

If the serpent takes 15 damage or more from an attack made by a creature or object it can see, it makes a tail attack against the attacker.

About Sea Serpent

Sea Serpent is a gargantuan monstrosity with a Challenge Rating of 16. It has a chaotic evil alignment.

In combat, this creature maintains an Armor Class of 17 and possesses 247 hit points (derived from 15d20+90).

GM Tips: Using Sea Serpent

1 tips available

When using Sea Serpent in your D&D 5e campaign, consider these tactical approaches:

Aquatic Combat: This creature can swim at 50 ft. It has advantage in water environments. Consider fighting on land or using water-based spells against it.

Player Guide: Facing Sea Serpent

1 strategies available

When your party encounters this creature, keep these strategies in mind:

Aquatic Combat Defense: This creature can swim at 50 ft! It has advantage in water. Fight on land if possible. Use 'Control Water' or drain water sources to limit its mobility.

Encounter Building Calculator

Standard Party Encounter (4-5 characters):

This creature is a medium encounter for a party of 4 characters of level 16.

Solo Encounter:

A single character of level 20 (up to level 20) can face this creature in a medium to hard encounter.

Experience Point Thresholds:

Medium: 27,200 XP
Hard: 40,800 XP
Deadly: 54,400 XP

Based on D&D 5e Dungeon Master's Guide encounter building guidelines. CR roughly equals party level for medium encounters.

Frequently Asked Questions

What is the challenge rating of Sea Serpent?: Sea Serpent has a Challenge Rating of 16, making it appropriate for parties of level 16.0.
What type of creature is Sea Serpent?: Sea Serpent is a Gargantuan Monstrosity, which affects how certain spells and abilities interact with it.