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Image prompthuge rooted plant creature, towering formation of hollow crystalline reeds and bamboo tubes riddled with holes, wind moaning and droning through the openings, visible ripples of sound bleeding from pores, whip-like lashing fronds, unmovable anchored trunk, unleashing a thunderous sonic shriek shockwave, desolate cracked rocky waste, pale bone-grey and dusty green stalks with mineral crust, worm's-eye scale, ominous resonance, dark fantasy, grimdark, painterly digital art, dramatic chiaroscuro lighting, muted desaturated palette with corrupted-crimson accents, weathered post-Cataclysm atmosphere, intricate high detail, cinematic composition

Sussurus

Huge Plant, Unaligned
CR 6
AC 15 (natural armor)
HP 133 (14d12 + 42)
Speed 20 ft.
STR
20
+5
save +5
DEX
8
−1
save −1
CON
17
+3
save +6
INT
2
−4
save −4
WIS
14
+2
save +2
CHA
3
−4
save −4
Resistances Piercing, Slashing
Immunities Thunder; Blinded, Charmed, Deafened, Frightened
Senses Tremorsense 90 ft.; Passive Perception 12
Languages —

Traits

Keening Wind. Holes in the Sussurus's body constantly produce a shrill droning noise. Every enemy within 60 feet that can hear it:

  • Has Disadvantage on hearing-based Wisdom (Perception) checks.
  • Must make a DC 14 Constitution save when attempting to cast a spell with a Verbal (V) component. Failure: The spell fails, and the spell slot is not expended.

Deafened creatures are not affected by this feature. The Silence spell completely suppresses the Sussurus's drone.

Rooted. The Sussurus can't be knocked Prone or forcibly moved.

False Appearance. While motionless, it is indistinguishable from an ordinary crystal/bamboo formation (DC 16 Intelligence (Nature)).

Actions

Multiattack. It makes three Lashing Frond attacks.

Lashing Frond. Melee Attack Roll: +8, reach 15 ft. Hit: 14 (2d8 + 5) Slashing damage.

Sonic Burst (Recharge 5–6). The Sussurus's drone turns into a deafening shriek. Every creature within a 30-foot Emanation must make a DC 14 Constitution save.

  • Failure: 27 (6d8) Thunder damage, and the target is Deafened for 1 minute. In addition, if the target is maintaining Concentration, its Concentration is automatically broken.
  • Success: Half damage, not Deafened.

How to Use

The Sussurus is a siege monster that silences casters. But its solution is very clear:

Keening Wind doesn't affect Deafened creatures.

This is a deliberate design. If the party notices this, they can win the encounter by deafening themselves — earplugs, Silence, or even deliberately accepting Deafened from Sonic Burst. The "your weakness becomes your strength" moment gives a perfect sense of discovery at the table.

Give a hint: have a NPC or a corpse nearby carrying wax earplugs. Or have a creature living near the drone be deaf. Let the players make the connection.

Somatic-only casters have an advantage: a Sorcerer with Subtle Spell, or spells without a V component (rare but they exist), are unaffected.

Balance Note

The "spell slot is not expended" part matters. The Sussurus blocks the spell, it doesn't burn the resource. The caster gets annoyed but doesn't get poorer. This distinction is the difference between a "tough opponent" and a "fun killer."

For a 4-person Lv7 party, a single Sussurus = 2,300 XP, budget (Medium) 1,300×4 = 5,200. Low. Use it as an arena/location hazard: while the party fights something else, the Sussurus drones in the background and hampers the caster.