Sire of Stagnation

Gargantuan aberration, chaotic evil

Armor Class

18 (natural armor)

Hit Points

310 (20d20+100)

Speed

50 ft.

Saves

Str +1 3, Con +11 r Wis +8

Skills

Perception +8

Damage Immunities

psychic; bludgeoning, piercing, and slashing from nonmagical weapons

Condition Immunities

charmed, frightened

Senses

darkvision 120 ft.

Languages

Eldrazi, telepathy 120 ft.

Challenge

17

Alien Mind

The sire has advantage on Wisdom saving throws.

Blighted Trail

Terrain that the sire passes over turns to white ash. Plants are destroyed in that area and cannot regrow for 1d10 days.

Ingest Scion

As a bonus action, the sire can ingest an eldrazi scion within 15 feet of it, destroying the scion. The sire then regains 16 (3d10) hit points.

Scourfrom Existence

When the sire reduces a creature to 0 hit points, that creature's body becomes a pile of white dust.

Actions

Multiattack

The sire makes four fist attacks.

Fist

Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 20 (2d12+7) bludgeoning damage.

Maddening Roar (Recharge 6)

The sire emits a mind-shattering roar. Each creature of the sire's choice within 100 feet of it and able to hear the roar must make a DC 18 Wisdom saving throw. On a failed save, a creature takes 44 (8d10) psychic damage and is afflicted with short-term madness (Dungeon Master's Guide pg. 259). On a successful save, the creature takes half as much damage and isn't afflicted with madness.