Viper tree

Viper trees were a strange mixture of demon, plant and reptile found in the Lower Planes. As of 1370 DR there were reports that several Red Wizard zulkirs had brought specimens from the Abyss and planted them in Thay.

Description
In the larval stage, viper trees were fully mobile and appeared to be three-headed snakes (all heads at the same end) with the middle head smaller than the other two. After they planted themselves, they could be mistaken for beech trees or other similar trees with light-colored, smooth bark, at a distance. Up close, the reptilian nature was easily noticeable with scaly white skin and a snake head at the end of each branch. A mature viper tree had dozens of branches.

Behavior
After hatching, viper tree larvae were insatiably hungry with only animal intelligence, feeding on small prey such as cranium rats. For the first month or so, the middle head was dormant until at some point it awakened and became the guiding intelligence of the creature, seeking out a good place to put down roots. After killing a manes or other suitably large prey, the larva skewered the carcass as it drove its tail into the ground to begin the plant phase, thus providing nourishment for the heads and fertilizer for the soil.

As the viper tree grew, the intelligent head was absorbed back into the trunk where it became the heartwood of the tree. The branches could still move like snakes when necessary, but mostly swayed in imitation of a regular tree in a breeze, regardless if any wind was present or not. At this stage, viper trees could speak in a susurrant version of Abyssal and often whispered to each other at night, bragging about their kills, whining about their hunger, or gloating over the treasure strewn about their trunk.

Once planted, a viper tree could live off the soil but also ate whatever it could subdue and swallow. Individual viper trees rarely attempted to kill anything bigger than Small-sized creatures, but in numbers, like a grove of trees, they were much more aggressive, attacking even small groups of Medium-sized creatures. Given enough time, viper trees could consume even Large creatures.