Mushroom Thyrno
Mushroom Thyrno — The Encounter
Hooded toadstool-sprite who hurls glowing spore-bombs · a boss your table can run with almost no prep. SRD 5.1-compatible.
Who Is Mushroom Thyrno
The thyrno are the bomb-tenders of the Ashitake fungal warrens, hatched where rot meets moonlight. From the day a spore-child first flowers a cap, it is set to apprentice among the satchel-makers, learning which mushroom weeps poison and which merely glows. They bind those distillations into glass flasks slung across the chest, and they wear the red scarf so that no rival warren may read the trembling of their lips as they count fuses. A thyrno fights as it forages: never in the open, always from behind a stalk, lobbing a luminous bomb and vanishing into its own spore-smoke before the cloud clears. Folk who walk the deep wood at dusk report little hooded shapes that scatter like startled toads, leaving behind only a faint sweet reek and a ring of dead grass. Treat one gently and it may trade you a healing cap; corner one and its whole bandolier becomes your problem.
Run Mushroom Thyrno in Sixty Seconds
- It is a bomber, not a brawler — open with a Spore Bomb on the tightest knot of PCs, apply the poisoned condition, then never stand and trade.
- Kill-priority — it wants the back line; if it keeps poisoning your caster, run it down or it will whittle the party from cover.
- Mind the death — Volatile Satchel pops 2d6 poison in a 5-foot burst when it dies, so do not finish it while hugging it.
- When pressured — Skitter to Disengage and Spore Cloud Step into obscurement; it should always end its turn behind a stalk.
- Three ways to run it — a sneaky duo of poison-lobbers, a screen of spore-bombers in front of a fungal boss, or a tradeable ally that heals with its Healing Cap.
Mushroom Thyrno
Small fey, chaotic neutral
CR 2 · 450 XP · GUIDELINESpore Cloud Step. When the thyrno takes the Hide action, it bursts into a puff of luminous spores and becomes lightly obscured to creatures more than 5 feet away until the start of its next turn, gaining advantage on the check.
Volatile Satchel. When the thyrno drops to 0 hit points, its alchemical bandolier ruptures. Each creature within 5 feet must succeed on a DC 12 Dexterity saving throw or take 7 (2d6) poison damage.
Actions
Multiattack. The thyrno hurls one Spore Bomb, then makes one Toadstool Dagger attack.
Spore Bomb. Ranged Weapon Attack: +5 to hit, range 30/60 ft., one target. Hit: 9 (2d6+2) poison damage, and the target must succeed on a DC 12 Constitution saving throw or be poisoned until the end of its next turn.
Toadstool Dagger. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (1d4+3) piercing damage plus 2 (1d4) poison damage.
Bonus Actions & Reactions
Skitter. Bonus Action. The thyrno takes the Disengage or Dash action, darting between mushroom stalks and cover.
A knee-high sprite crowned with a red, white-spotted toadstool cap, swaddled in ragged crimson robes and a face-scarf, magenta eyes glowing beneath the hood as it juggles a brace of bubbling, light-filled bomb-flasks.
Mushroom Thyrno, Bound
Companion · acts on your initiative
Bound · GUIDELINEHealing Cap (signature). Once per short rest, as an action, the thyrno presses a glowing cap to an ally within 5 feet, restoring 7 (2d6) hit points.
Actions
Spore Bomb. Ranged Weapon Attack: +5 to hit, range 30/60 ft., one target. Hit: 9 (2d6+2) poison damage.
Reactions
Smoke Out. When an ally within 10 feet is targeted by an attack, the thyrno cracks a spore-flask, granting that ally a +2 bonus to AC against that attack.
Won over with a fair trade, the bound thyrno trots at heel lobbing bombs at foes and pressing healing caps on friends, all the while muttering counts under its scarf.
Guideline numbers — formula-tuned and read from the miniature's design, not yet table-proven. Tell us how it ran in the comments.
How It Fights — by Tier
Same creature, scaled threat. The traits never change; only the numbers move.
Open with a Spore Bomb at the most clustered foes, then Skitter behind cover and Hide into its spore cloud. Kill-priority: drop it before it pokes a wounded PC, and keep 5 feet clear when it dies so the Volatile Satchel does not catch your party. Pair a pack of two or three with a tougher front-line brute that the thyrnos can chip and poison around.
Run it as a harrying skirmisher beside a bigger threat: bombs to soften clusters, then vanish into spore-smoke. Focus fire it down early since the poison stacks fast against casters. Best used in numbers or in a fungal lair, never as the centerpiece.
At this tier it is the bomber pet of a flagship fungal horror, peppering the party while the boss commits. Have it stay obscured and target the squishiest line; the death-burst punishes melee that ignores it. Pair it with a bigger threat or a swarm of lesser fungal kin, not alone.
Put Mushroom Thyrno on the table
Download the presupported STL and run the fight tonight — the model, and the encounter that comes with it.
Get the STL on MyMiniFactory →Clay Cyanide Companion Rules v1
How a bound creature acts
- A companion acts on its owner's initiative, immediately after the owner.
- It uses the Companion block above — roughly ×0.6 HP and damage, no recharge abilities, and at most one reaction trait.
- It moves freely; it takes its Action only while its owner is conscious.
- At 0 HP a companion is broken, not dead — restored on a long rest unless your table rules otherwise.
Original Clay Cyanide material © Clay Cyanide LLC — explicitly not the non-SRD official sidekick rules.
Questions, Asked at the Table
What CR is Mushroom Thyrno?
Its home tier is CR 2 (450 XP) for a tier 1 party of levels 1-4: AC 14, 44 HP, +5 to hit, save DC 12. Scaled stat lines for tier 2 (levels 5-10) and tier 3 (levels 11-15) are provided so you can drop it beside higher-level threats.
Can Mushroom Thyrno be a companion or ally?
Yes. The Thyrno, Bound profile (AC 14, 26 HP) trots beside the party lobbing Spore Bombs, screens an ally with Smoke Out, and patches wounds with its once-per-rest Healing Cap. It is a fragile support skirmisher, not a front-liner.
Is Mushroom Thyrno a good solo boss?
No. It is an add-on skirmisher with no legendary actions, built to harry from cover. A four-player party will out-act it quickly, so deploy it in numbers or as the bomb-tender of a larger fungal threat rather than as a lone centerpiece.
Tell Us How It Ran
This work includes material taken from the System Reference Document 5.1 ("SRD 5.1") by Wizards of the Coast LLC and available at dnd.wizards.com/resources/systems-reference-document. The SRD 5.1 is licensed under the Creative Commons Attribution 4.0 International License available at creativecommons.org/licenses/by/4.0/legalcode.
Clay Cyanide Miniatures is not affiliated with, endorsed, sponsored, or specifically approved by Wizards of the Coast LLC. This content is compatible with the fifth edition of the world's most popular fantasy roleplaying game. Companion rules, lore, names, and original mechanics © Clay Cyanide LLC.
Technical Specifications
32mm, 75mm
STL, Pre-supported STL
Standard or ABS-like resin, 0.05mm layer height
Yes — ready to print, optimized supports included
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