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Mu Spore

Gargantuan plant, chaotic neutral

Armor Class 20 (natural armor)
Hit Points 472 (27d20 + 189)
Speed 40 ft., fly 30 ft.

30 (+10) 9 (–1) 25 (+7) 18 (+4) 15 (+2) 19 (+4)

Saving Throws Dexterity +6, Constitution +14, Wisdom +9, Charisma +11
Skills Insight +9, Nature +11, Perception +9
Damage Immunities acid, poison; bludgeoning, piercing, and slashing from nonmagical weapons
Condition Immunities blinded, charmed, deafened, exhaustion, paralyzed, poisoned, stunned
Senses blindsight 240 ft., passive Perception 19
Languages Common, Deep Speech, Terran, Undercommon
Challenge 23 (50,000 XP)

Special Traits

  • Freedom of Movement. The mu spore ignores difficult terrain, and magical effects can’t reduce its speed or cause it to be paralyzed or restrained. It can spend 5 feet of movement to escape from nonmagical restraints or being grappled. Being underwater imposes no penalties on the mu spore’s movement or attacks.
  • Grasping Tendrils. Sticky, arm-length tendrils cover the mu spore. Whenever a creature begins its turn within 5 feet of the mu spore, the creature must make a DC 20 Dexterity saving throw or be grappled (escape DC 20). The mu spore has no limit to the number of creatures it can grapple in this fashion and it does not suffer from the grappled condition while grappling other creatures with its grasping tendrils. A tendril can also be attacked and severed (AC 15; hp 10; immunity to acid, poison, and nonmagical bludgeoning, piercing, and slashing damage).
  • Legendary Resistance (3/day). If the mu spore fails a saving throw, it can choose to succeed instead.
  • Siege Monster. The mu spore does double damage to objects and structures.


  • Multiattack. The mu spore makes three attacks: one with its bite and two with its tendrils.
  • Bite. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 28 (4d8 + 10) piercing damage. If the target is a Large or smaller creature grappled by the mu spore, that creature is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside the mu spore, and it takes 42 (12d6) acid damage at the start of each of the mu spore’s turns. A mu spore can have four creatures swallowed at a time. If the mu spore takes 50 damage or more on a single turn from a creature inside it, the mu spore must succeed on a DC 28 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the mu spore. If the mu spore dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 20 feet of movement, exiting prone.
  • Tendrils. Melee Weapon Attack: +17 to hit, reach 40 ft., one target. Hit: 24 (4d6 + 10) bludgeoning damage, and the target is grappled (escape DC 20). Until the grapple ends, the target is restrained. The mu spore has 10 feeder tendrils, each of which can grapple a target.
  • Fling. One Large or smaller object held or creature grappled by the mu spore is thrown up to 60 feet in a random direction and knocked prone. If a thrown target strikes a solid surface, the target takes 3 (1d6) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 18 Dexterity saving throw or take the same damage and be knocked prone
  • Spore Cough (Recharge 5-6). The mu spore releases a cloud of burrowing spores in a 120-foot cone. Creatures in the affected area must make a DC 20 Constitution saving throw or take 90 (20d8) poison damage, or half as much damage on a successful save.

Legendary Actions

The mu spore can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The mu spore regains spent legendary actions at the start of its turn.

  • Tendril Attack or Fling. The mu spore makes one tendril attack or uses its Fling.
  • Constrict (Costs 2 Actions). All creatures grappled by the mu spore must make a DC 20 Constitution saving throw. On a failed save, they take 24 (4d6 + 10) bludgeoning damage, or half as much damage on a successful one.
  • Spore Blast (Costs 3 Actions). The mu spore releases a large blast of spore-laden air from itself in all directions. Creatures within 15 feet of the mu spore that aren’t grappled by it must make a DC 21 Strength saving throw or be pushed back 15 feet and knocked prone.
Section 15: Copyright Notice

Rappan Athuk © 2018, Frog God Games, LLC; Authors Bill Webb, Clark Peterson, Skeeter Green, Tom Knauss, Lance Hawvermale, WDB Kenower, Casey Christofferson, and Greg Raglund; based on the original creation of Bill Webb.