I decided to make this creature after spending an hour pulling bindweed out of my backyard. Inspired by invasive and/or aggressive vining plants such as poison ivy, kudzu, and bindweed!
Though called a hydra due to its tendency to regenerate from very little plant material and many nodding flower heads, the twining hydra is not related to hydras in the least. Twining hydras are thought to arise from the chaotic energy of the First World, though some theorize that they are a biological deterrent created by a gnomish druid to drive intruders away from sacred groves. Either way, the capacity of the creatures for destruction is unparalleled and their persistence overly robust. Attempts to remove the creatures result in severe allergic reactions from the caustic sap, and attempts to hide are typically foiled by the plant simply tearing down entire walls. Even so, the sap is a useful reagent in alchemical poisons and decoctions when handled carefully, so adventurers may seek out one of these invasive creatures rather than simply defending against its encroachment on farmland or civilization.
Twining Hydra Creature 9
N Huge Plant
Perception +18, lifesense (precise) 30ft (no vision)
Skills Athletics +20 (can't jump or swim), Stealth +18
Str +6 Dex +5 Con +4 Int -5** Wis** +3 Cha -2
AC 27 all-around vision; Fort +21, Ref +18, Will +13
HP 160 regeneration 35 (deactivated by acid or negative, or see Sunlight Dependence below); Immunities visual; Resistances piercing 10, bludgeoning 10; Weaknesses fire 10
Attack of Opportunity ⟳
Phototropic ⟳ (primal, healing) Trigger The Twining Hydra is affected by or in the area of a spell with the Light trait; Effect The Twining Hydra Steps towards the light source and regains 40 HP
Speed 20 feet, climb 15 feet
Melee ◆ vine +19[+14/+9] (reach 10ft), Damage 2d8+11 bludgeoning plus Grab
Constrict ◆ 2d8+9 bludgeoning, DC 25
Sap Spray ◆◆ The twining hydra snaps one of its own vines to spray caustic milky sap in a 30-foot cone. Creatures in the area must succeed at a DC 25 Reflex save or be exposed to Irritating Sap.
Irritating Sap (contact poison) Similar to poison ivy, the twining hydra produces an allergic reaction, causing blistering, itching, and pain in affected areas that becomes more severe with repeated exposure. Unlike other afflictions, Irritating Sap can only progress to a stage equal to the number of times a creature has been exposed to it (so if a creature has been exposed two times, it can only progress between Stages 0-2).
Saving Throw DC 25 Fortitude; Maximum Duration 3 days; Stage 1 4d6 poison damage and enfeebled 1 (1 day); Stage 2 6d6 poison damage and enfeebled 1 (1 day); Stage 3 8d6 poison damage, enfeebled 1 and drained 1 (1 day); Stage 4 death
Aerial Roots A Twining Hydra ignores the first 5 points of Hardness when damaging an object or structure (including shields and animated objects).
Sunlight Dependence A Twining Hydra does not need to eat, although it does require sunlight to live. Depriving a Twining Hydra of all light for 1 week deactivates its regeneration.