It's no secret that plants tend to congregate at the lower and middle CRs, and that dragons tend to hang out more at the higher end of the scale. As a result, the two tend not to get together very much. So, naturally, it seemed like a great idea to mix them together and see what happens. It's a dragon! It's a plant! It's the dragonvine!
Dragonvine
At first glance, this creature could almost pass for a green dragon, but closer inspection reveals that its body is comprised of a coiling and twisting knot of vines, which have grown together to form a body much like that of a dragon, including a pair of massive, ragged, leaf-covered wings, four legs like mighty oaks, and a maw dripping with acidic sap and lined with sharp thorns.
DRAGONVINE CR 16
XP 76,800
N Huge plant
Init +2; Senses low-light vision, tremorsense 60 ft.; Perception +5
Aura pollen (30 ft., DC 28)
DEFENSE
AC 32, touch 10, flat-footed 30 (+2 Dex, +22 natural, -2 size)
hp 252 (24d8+144)
Fort +20, Ref +10, Will +13
Defensive Abilities amorphous; DR 15/magic, 5/adamantine; Resist cold 10, fire 20; Immune electricity, mindless, plant traits; SR 37
OFFENSE
Speed 40 ft., fly 80 ft. (clumsy)
Melee bite +24 (2d8+8 plus grab), 2 claws +24 (2d6+8), 2 wings +19 (1d8+4), tail slap +19 (2d6+12)
Space 15 ft.; Reach 10 ft.
Special Attacks breath weapon (60-ft. cone, 18d6 piercing damage, Reflex DC 28 for half, usable every 1d4 rounds), swallow whole (10d6 acid damage and 10d6 slashing damage, AC 21, 50 hp)
STATISTICS
Str 26, Dex 14, Con 22, Int —, Wis 20, Cha 8
Base Atk +18; CMB +28; CMD 40
SQ compression, drain nutrients, resilient insides
ECOLOGY
Environment any
Organization solitary
Treasure double
SPECIAL ABILITIES
Drain Nutrients (Ex): A dragonvine has numerous tendrils inside it which serve a function similar to roots in stationary plants. These tendrils bore into the creatures the dragonvine swallows whole and drains them of their nutrients. If the dragonvine begins its turn with a creature swallowed inside of it, these vines cause the dragonvine to heal 15 hit points, and its Strength and Dexterity scores each increase by +4 until the beginning of its next turn.
Pollen Aura (Ex): A dragonvine constantly exudes a cloud of pollen spores, which are highly debilitating to non-plant creatures. Each creature within 30 feet of the dragonvine must succeed on a Fortitude save (DC 28) or become sickened for as long as he remains within 30 feet of the dragonvine, and for 1 minute thereafter. Creatures that fail their save by 10 or more are nauseated for 1 minute, instead, and if they are still within 30 feet of the dragonvine after that time, they are sickened for as long as they remain within 30 feet of the dragonvine, and 1 minute thereafter. Creatures that roll a natural 1 on their saving throw to resist the effects of the pollen are paralyzed for 1 minute, in addition to these effects.
Resilient Insides (Ex): The inside of a dragonvine is particularly difficult to pierce, and it takes twice as much damage to cut one's way out from inside its stomach (this is reflected in its statistics).
Ecology
There are many monsters that are believed to have originally come from the laboratories of mad wizards, but the dragonvine is one of the rare cases where this is largely known to be fact. The process of creating a dragonvine was first pioneered by Kiaped Rosco, a wizard with a particular love of gardening and topiary, who claims that the idea came to him in a dream as he lay sleeping beneath an oddly-shaped elm tree. Whatever the case, Kiaped quickly marketed his services creating the things, and began supplying them to anyone who wanted a massive plant dragon to guard their lands—provided they were able to pay his fee, that is. Eventually, Kiaped grew too old to create the things himself, and transitioned to selling instruction books that explain how one can create them, and from these books, the secret eventually leaked out.
To date, very few dragonvines have escaped into the wild or otherwise been left to their own devices, so they can't truly be said to have an ecology. They are incapable of producing more of their kind, and can only be created by spellcasters. They have a voracious appetite, and, unless magically controlled, are prone to spending all of their time hunting down and devouring prey.
Dragonvine Creation
Dragonvines can be created in a fashion similar to crafting constructs, even though they are plants.
CL 18th; Price 280,000 gp
Feats Craft Construct; Spells animate plants or shambler
Special creator must be at least CL 18th; Skills Profession (herbalist) DC 22; Cost 140,000 gp