Eldrathema

Eldrathema are large, floating culminations of external organs and eldritch anatomy. Their large mouths are located at the top of their "body".

**Armor Class:**18

**Hit Points:**  190 (20d10+90)

**Speed:**fly 60 ft.

**Proficiency Bonus:** +6

**Damage Resistance:** lightning, thunder; bludgeoning, piercing, and slashing from nonmagical attacks that aren't silvered

**Damage Immunities:** acid, necrotic, psychic

**Damage Vulnerabilities:** radiant

**Condition Immunities:** charmed, exhaustion, frightened, grappled, poisoned, prone, restrained

**Senses:** blindsight 120 ft., passive perception 15

**Languages:** Deep Speech

**Challenge Rating:** 16 (15,000 XP)

## Abilities

### Traits

***Spellbane Fluctuation:*** Within 60 feet of the eldrathema, the magic continuum warps and bends around it due to its extradimensional qualities. Roll a 1d8 at the start of each round. On a 1 to 4, nothing happens. On a 5 to 6, spells become void for the duration of the round within 60 feet of the eldrathema. On a 7 to 8, a wild magic surge occurs.

***Magic Resistance:*** The eldrathema has advantage on saving throws against spells and other magical effects.

***Outer Horror:*** The eldrathema is from the Outer Plane, a realm of eldritch abominations, unimaginable horrors, and aberrant logic not known to Arcturus, the Aetheral Veil, or even Hell. A target fighting an eldrathema for the very first time must make a DC 21 Wisdom saving throw, or gain disadvantage on all attack rolls and saving throws against the eldrathema. If the target has fought an eldrathema before, then it must succeed on a DC 17 Wisdom saving throw.

***Sunlight Sensitivity:*** While in sunlight, the eldrathema has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.

### Actions

***Multiattack:*** The eldrathema makes three attacks.

***Bite:*** Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 22 (3d8+10) 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 eldrathema. A swallowed creature is blinded and restrained, it has total cover against attacks and other effects outside the eldrathema, and it takes 22 (6d6+4) acid damage at the start of each of the eldrathema's turns. If the eldrathema takes 45 damage or more on a single turn from a creature inside it, the eldrathema must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 20 feet of the worm. If the eldrathema dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 20 feet of movement, exiting prone.

***Horrifying Visage:*** Each non-undead creature within 60 feet of the eldrathema that can see it must succeed on a DC 16 Wisdom saving throw or be frightened for 1 minute. If the save fails by 5 or more, the target also ages 1d10 years. A frightened target can repeat the saving throw at the end of each of its turns, ending the frightened condition on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to this eldrathema's Horrifying Visage for the next 24 hours. The aging effect can be reversed with a greater restoration spell, but only within 24 hours of it occurring.

***Tendril:*** Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 19 (3d6+10) bludgeoning damage plus (2d4+2) lightning damage. If the target is a creature, it must succeed on a DC 17 Constitution saving throw or become diseased. The disease has no effect for 1 minute and can be removed by any magic that cures disease. After 1 minute, the diseased creature's skin becomes pale and blood begins to routinely exit through orifices, such as nostrils and ears. Every 2d8 hours, the creature takes 5 (1d6+2) acid damage, and vomits up blood and eldritch sludge. The creature cannot regain hitpoints if it is diseased. If the creature reaches 0 hitpoints, the creature's skin begins to rapidly peel off, and the creature dies as its body liquefies.