Crawling Glacier

Gargantuan ooze, neutral

Armor Class 19 (Natural Armor)
Hit Points 492 (24d20 + 240)
Speed 5 ft., swim 5 ft.

Str	Dex	Con	Int	Wis	Cha
30 (+10)	1 (-5)	30 (+10)	1 (-5)	1 (-5)	1 (-5)

Skills Perception +2, Survival +2
Damage Vulnerabilities fire
Damage Immunities cold
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained, stunned
Senses blindsight 120 ft., tremorsense 240 ft.; passive Perception 2
Languages understands Titan Speech but cannot speak.
Challenge 23 (50,000 XP)

Special Traits

• Cold Aura. Within a radius of 300 feet a crawling glacier decreases the environmental temperature by 40 degrees Fahrenheit (5 degrees Celsius). This cold aura persists for 2d4 days after the creature leaves the area or has been killed.
• Keen Smell. The crawling glaciers have advantage on Wisdom (Perception) checks that rely on smell.
• Cold Healing. A crawling glacier regains 20 hit points at the start of its turn, but only if the ambient temperature outside its cold aura is 32 degrees Fahrenheit (0 degrees Celsius) or below. The crawling glacier dies only if it starts its turn with 0 Hit Points and doesn’t cold heal.
• Magic Resistance. The crawling glacier has advantage on saving throws against spells and other magical effects.

Actions

• Engulf. The ooze moves up to its speed. While doing so, it can enter Gargantuan or smaller creatures’ spaces. Whenever the cube enters a creature’s space, the creature must make a DC 20 Dexterity saving throw. On a successful save, the creature can choose to be pushed 5 feet back or to the side of the ooze. A creature that chooses not to be pushed suffers the consequences of a failed saving throw. On a failed save, the ooze enters the creature’s space, and the creature takes 21 (6d6) acid damage, 21 (6d6) cold damage and is engulfed. The engulfed creature can’t breathe, is restrained, and takes 21 (6d6) acid damage and 21 (6d6) cold damage at the start of each of the cube’s turns. When the cube moves, the engulfed creature moves with it. An engulfed creature can try to escape by taking an action to make a DC 20 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the cube.
• Slam. Melee Weapon Attack: +17 to hit, reach 15 ft., one target. Hit: 24 (4d6 +10) bludgeoning damage plus 21 (6d6) cold damage.

About

Occasionally it is said that these creatures appear randomly overnight, looming where nothing previously stood. Further examination, even from a distance, reveals beams, trees, large animal skeletons and even a section of a timber wall inside. They are not frozen in place but rather drift slowly within the mass. A clear path behind the creature shows where it has moved.

Crawling glaciers are a rare but serious menace in cold, mountainous regions, capable of wiping away structures and even entire settlements as though they were never present to begin with. Tales tell of whole villages being consumed by a crawling glacier during long blizzards, when the threat could not be spotted until it was too late.

Crawling glaciers hunt by scent, and they consume any organic material they engulf. This typically includes herds of animals, forests, and settlements, Some who dwell in particular frigid areas, have developed tricks to change the creatures hunting route, such as enticing a direction change with a herd of animals, starting a large forest fire to drive it away or, of course, hiring a party of high-level mercenaries or heroes to harass it.

A typical crawling glacier is 15 – 30 feet high and 20 – 40 feet on a side, with crevasses and fissures all around its perimeter. Their weight is inestimable, as it varies not only with their dimension but with their contents.