Elder Remorhaz

Elder Remorhaz CR: 17

Gargantuan monstrosity , unaligned

Armor Class: 23

Hit Points: 340 25d20+181

Speed: 50 ft , burrow: 50 ft

STR

28 +9

DEX

14 +2

CON

24 +7

INT

6 -2

WIS

10 +0

CHA

5 -3

Saving Throws: Strength +15, Constitution +13

Skills: Perception +6, Athletics +15

Damage Immunities: Cold, Fire, Bludgeoning, Piercing, and Slashing from Nonmagical Attacks

Condition Immunities: Frightened

Senses: Darkvision: 60ft., Tremorsense 60ft, Passive Perception 16

Languages: --

Challenge Rating: 17 ( 18,000 XP)

Proficiency Bonus: +6

Heated Body. A creature that touches the remorhaz or hits it with a melee attack while within 5 feet of it takes 24 (4d12) fire damage.

Underworld Maw: immediately after the Elder Remorhaz takes the Rapid Burrow bonus action and if there is a creature of large or smaller size within the radius of 10ft, the Rehmoraz can make an addition bite attack using the same bite attack rules


Consuming Charge. If the Elder Remorhaz moves at least 20 feet straight toward a creature and then hits it with a bite attack on the same turn, that target must succeed on a DC 20 Strength or Dexterity saving throw or be grappled.

Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Actions

Bite. Melee Weapon Attack: +15 to hit, reach 25 ft., one target. Hit: 40 (8d12 + 9) piercing damage plus 18 (4d8) fire damage. If the target is a creature, it is grappled (escape DC 20). Until this grapple ends, the target is restrained, and the remorhaz can't bite another target.

Molten Spray: The Elder Remorhaz has learned, over the course of it's life, to spray out chunks of molten earth at it's prey. Range: 60ft Cone. Dexterity Saving throw DC 21 or take (10d10) fire damage and become restrained. On a success, the targets take half damage and are not restrained. After the Remorhaz uses this ability, roll 1d4. On a 4, it recharges.

Swallow. The remorhaz makes one bite attack against a large or smaller creature it is grappling. If the attack hits, that creature takes the bite's damage and is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside the remorhaz, and it takes 32 (8d8) acid damage at the start of each of the remorhaz's turns.
If the remorhaz takes 50 damage or more on a single turn from a creature inside it, the remorhaz must succeed on a DC 15 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 15 feet of the remorhaz. If the remorhaz dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 30 feet of movement, exiting prone.

Bonus Actions

Rapid Burrow: As a bonus action, the Elder Remorhaz can burrow under most surfaces, and reappear anywhere within 60 ft. Anything caught in a 20ft radius of the Remorhaz's arrival must succeed on a DC 17 Dexterity saving throw or take (3d10) bludgeoning damage and be knocked out of the 20ft radius and become prone. On a success, the creatures take half as much damage and are not knocked prone, but are still pushed away.

Legendary Actions

The Elder Remorhaz can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The Elder Remorhaz regains spent legendary actions at the start of its turn

1. Bite. The Elder Remorhaz makes a bite attack against a target, which can include a grappled or restrained creature
2. Rapid Burrow: The Elder Remorhaz burrows anywhere within 60 ft, and can use it's Underworld maw feature
3. Molten Spray: The Elder Remorhaz uses it's Molten Spray ability if it is recharged and available

Suggested Environments

High Mountains
Arctic
Tundra