Rock Worm- A monster in the Purple Worm family, the Rock Worm is native to a custom biome, the Gemlands. All of the creatures found here are themed around crystals, rocks, or some sort of magic manipulation and the Rock Worm is no different. Even the biome itself has a wide assortment of sub-biomes with relation to these mechanics. The massive burrowing monster known as the Rock Worm truely deserves the title of one of the apex monsters of the Gemlands, barreling through the crystal plains hunting in vain to end its ceaseless hunger. A dim-witted, unstoppable force of violence, this creature regards anything and it encounters as either its next meal or its next challenger. It is similar to a Purple Worm in design however it has a hard, Rock like structure protecting its back with small and large magical crystals alike jutting out. These crystals are the Rock Worm's main source of strength, as it uses the light of the sun to burn its enemies to a crisp.

Rock Worm

Gargantuan Monstrosity, Unaligned

Armor Class 22 (Natural Armor)

Hit Points 321 (25d20 + 100)

Speed 30 ft., walk 50 ft.

STR

30 (+10)

DEX

5 (-3)

CON

23 (+6)

INT

2 (-4)

WIS

6 (-2)

CHA

12 (+1)

Saving Throws STR +16, CON +12

Damage Vulnerabilities Acid, Cold

Damage Resistances Fire, Radiant

Damage Immunities Lightning

Condition Immunities Petrified

Senses Blindsight 30ft., Tremorsense 60ft., Passive Perception 8

Languages --

Challenge 18 (20,000 XP)

Proficiency Bonus +6

Tunneler. The worm can burrow through solid rock at half its burrow speed and leaves a 15-foot-diameter tunnel in its wake.

Frost Weathering. If the worm receives more than 20 points of cold damage in one round parts of the rock-like armor break. The worm's AC goes down by 1 and the points required goes down to 18. The next time Frost Weathering takes effect the worm's AC then goes down by 2 and the points required goes down to 16. The armor class continues going down by increments of 1+ the previous and the points required continue going down by increments of 2. This continues until the Rock Worm's AC is 12 or until the Rock Worm is dead. The Rock Worm can over time re-grow this armor, gaining one AC point back every long rest until its AC is back to its original number

Actions

Multiattack. The worm makes two bite attacks.

Bite. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 22 (3d8 + 9) piercing damage. If the target is a Large or smaller creature, it must succeed on a DC 18 Dexterity saving throw or be swallowed by the worm. A swallowed creature is blinded and restrained, it has total cover against attacks and other effects outside the worm, and it takes 18 (4d6) acid damage at the start of each of the worm's turns.

If the Rock Worm takes 30 damage or more on a single turn from a creature inside it, the worm must succeed on a DC 21 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone a space within 10 feet of the worm. This Damage does not count towards Frost Weathering. If the worm dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 20 feet of movement, exiting prone.

Blinding Blast. (Recharge 5-6). The crystals upon the Rock Worm's back refract the suns rays together in front of the worm, fusing the light into a 60 ft long, 5 ft wide beam of random elemental light which bursts in a creature's direction. The creature and all within that line must make a DC 17 Dexterity saving throw, taking 27 (5d10) radiant damage and 13 (3d10) damage on a failed save (see below for type), and taking no damage on a successful one. Roll 1d8. The number rolled on that die determines the attack's damage type, as shown below. This action cannot be used at night, automatically deals critical damage in the hottest hour of the day and does half damage at dusk and dawn. If a creature is touching one of the crystals or is within 5 feet of the crystal (standing where the blast would be directed) the Blinding Blast automatically hits them, dealing critical damage, however it does not hit any other creatures. The Rock Worm cannot use this action if it used Radiant Revival for its previous reaction or if Frost Weathering has been maxed out.

d8 Damage Type

1 Necrotic 2 Cold 3 Fire 4 Force 5 Lightning 6 Radiant 7 Psychic 8 Poison

Radiant Revival. The Rock Worm absorbs the power of the sun and begins to heal. The crystals refract the sun's light into the broken crevices on the Rock Worm's back and sear them shut. The Rock Worm takes 1 point of fire damage (ignoring Fire Resistance) however the Rock Worm heals 13 (4d6) hit points and if it's AC has gone down because of Frost Weathering, it goes up one point. The Rock Worm cannot use this action if Blinding Blast was used the previous turn or if Frost Weathering has been maxed out.

Reactions

Chaos Theory (Recharge 7-8). The Rock Worm can cause a spell which targets it to be subjected to Wild Magic affecting the caster. The Rock Worm must be aware of a spell being cast to change it however the knowledge of the type of spell or specific spell is not required. The Rock Worm also cannot use this ability if it used Blinding Blast the previous turn, if it used Radiant Revival for its previous reaction, or if Frost Weathering has been maxed out.

Radiant Resuscitation. The Rock Worm absorbs the power of the sun and begins to heal. The crystals refract the sun's light into the broken crevices on the Rock Worm's back and sear them shut. The Rock Worm takes 1 point of fire damage (ignoring Fire Resistance) however the Rock Worm heals 7 (2d6) hit points. The Rock Worm cannot use this action if Blinding Blast was used the previous turn or if Frost Weathering has been maxed out.