A ruined fortress stands tall above these seaside cliffs. The bones of a large dragon lay forgotten below the ruins, shadowed by ferns which rustle gently in the breeze. It blows through the cliffs below, sometimes creating a ghostly wail. A small brook babbles past it, ignorant of the pain and suffering which once graced this land.
When the ship you bought passage on is wrecked in a terrible storm, your party washes ashore on an uncharted island. Around you towers the ruins of an ancient fortress, long overgrown with flowers and vines. Very little remains of its original inhabitants. The bones of a large dragon lie forgotten below the ruins, also overgrown.
Hiking up the steep pathways you find the bones of a man, covered in the tattered remnants of an oiled coat. Beneath that is a leather bound journal, covered with the same material but in much better condition.
While reading the journal you find brief notes of experiments on plants, made by a royal botanist. They detail his desperate attempts to change a yellow flowered plant into a weapon, in order to save his people from invading forces. While reading, you can hear the gentle rustling of animals in the brush around you.
You discover that many of his experiments failed, and learn how disheartened and desperate the botanist became. Eventually, however, one of his experiments succeeded. You read how it performs better than he ever dreamed, then his horror as it infects one of his assistants, then a member of the castle staff, then others.
The botanist fled when he discovered his creation could not be stopped. You learn that this isn’t the main castle at which he worked, but an outpost he was visiting on his attempt to seek passage off the island.
The last entry states “I have doomed us all, far worse than our enemy ever could. I wish everyone I knew was dead. But they’re not. They follow me, I can hear their voices, their growls as their vocal cords begin to rot and fall away in shreds. Still they pursue me. I am beginning to realize I could never escape. This is my penance for the doom I have brought upon my people.”
As you finish reading, the gentle rustling grows louder as rotting animals and humanoids covered in yellow flowers burst from the underbrush. At the tallest tower of the ruins waits their source—a huge sprawl of leafy vines and broad yellow blossoms…
What’s happening? Long ago a botanist created this plant as a weapon of war, but instead doomed all the inhabitants of the island to death. The plant is known to charm those who come near, calling them close enough so that it can drill tendrils into their brains and kill them.
It’s victims then rise, animated by the spores of the new plant that now grows within them; protecting the original plant while they can, then wondering afar to spread the spores when they finally collapse and decompose.