The creation of a fanatical order of dark druids intent on preserving the wilderness at any cost, the Black Seed can be a terribly destructive force. It is a small cylinder carved from some unknown wood, its surface pitted and scarred with bore marks and burls. A ring of gray stone is affixed to one end of the cylinder, and attached to this is a thin black leather thong which allows the cylinder to be worn as an amulet. If examined for magical properties, the Black Seed radiates Epic nature magic. An Epic test of divination magic will identify the power of the object, though it may not reveal the consequences of using this power.
The Black Seed has a singular power, thrice per day its owner can call forth a half-dozen tiny black seeds that trickle forth from the various burls and wormholes in the object. When cast upon the ground these seeds instantly bury themselves and begin to grow at a tremendous rate. Unplanted seeds vanish after one hour.
Each seed sprouts into a creeping weed-like plant that sends forth runners and shoots both above and below ground. These magical plants twist and bind around any cultivated plant they encounter, choking root, stem and branch in twisting, jagged tendrils. A single plant matures in a few hours, covering ten or fifteen square feet. Once mature, the plant blooms and goes to seed in the space of half an hour, each plant producing dozens of seed pods that pop open and spray their seeds up to thirty feet away, beginning the cycle anew.
Once it has cast its seed each mature plant metamorphoses into a secondary phase. Rigid, bamboo-like trunks shoot up from the ground, each sending forth dozens of thorn-lined, angular branches in all directions, creating a nearly impenetrable barrier. These plants are quite tough, requiring a heavy axe blow to sever a branch. Even fire is of little use against them, as it sears the surface but does not penetrate the plant's hard green trunks. This phase of growth culminates in a dense tangle of thorny growth, a dozen feet high, covering a vast area.
These spiky plants mature in the space of a single day, each sending forth dozens of massive blossoms that fill the air with a nauseating stench. Anyone exposed to the smell must make a Great test of toughness or be driven away, overcome by illness. These blossoms last a few hours, then quickly go to seed. Much like the original weed-like plant these seeds spray forth to cover a large area, though they are much less malevolent in nature. Each pod produces a dozen or more seeds of different types, each a species native to the area. These seeds root themselves among the creeping weeds and spiky hedges, then grow at an accelerated rate for one day before reverting to a more natural growth pattern.
A single seed will spread to cover up to a square mile before the potency of its magical growth fades. As the natural plants begin to grow the tangle of weeds and spikes begin to wither and die, collapsing into an organic sludge rich in nutrients. In as little as three days cultivated farmland can become a tangled scrub of wild grasses, underbrush and small trees, well on its way to becoming native forest.