Witherweed (5e Creature)
From D&D Wiki
Large plant, unaligned
Toxic Fumes. If the witherweed takes fire damage, it burns producing lethally toxic smoke. The cloud of smoke is a sphere with a radius in feet equal to the fire damage inflicted on witherweed (up to 20 ft.) The cloud spreads around corners, and its area is heavily obscured. The cloud lingers in the air for 1 minute. Each creature that is completely within the cloud at the start of the turn must succeed on a Constitution saving throw (DC 13) against poison or take 3d12 poison damage. Creatures that do not breathe or are immune to poison automatically succeed on the saving throw.
False Appearance. When the witherweed remains motionless, it is indistinguishable from an ordinary creeping plant.
Multiattack. The witherweed makes 1d4 Frond attacks.
Frond. Melee Weapon Attack: +2 to hit, reach 10 ft., one target. Hit: 1 poison damage and the target's Dexterity score is reduced by 1d4. The target is stunned if its Dexterity is reduced by 4 points this way, and incapacitated if this reduces its Dexterity to 0. The reduction lasts until the target finishes a short or long rest.
Witherweed is a spreading plant that can be be found in above-ground ruins, smothering walls and floors, obscuring doors and furnishings. The slightest touch of its fronds on bare skin causes uncontrollable shaking: the unwary can find themselves incapacitated and being slowly stung to death over the course of the day.
Beneath the fronds is a network of dry tubular strands that can undulate to gradually move the whole witherplant. Because of the plant's dryness and extensiveness, it might be tempting to burn away this dangerous weed, but to do so releases a thick smoke that is rapidly fatal to those who do not immediately vacate.
The witherweed's fronds remain potent even after the plant is killed. It can be harvested to create up to four 2 lb. bundles of fronds. Each, when set fire to, creates a 5 ft. radius of toxic fumes as described above. Each time a bundle is handled (for example, when harvesting it or setting it down) the handler takes a frond attack.