A bikepath runs along John Laurie, between the road and a set of backyards. One of them is so dense with trees and sod and fungus that it is like a small forest. The fence is old and decaying and shot enough that it never truly provided an obstacle. Jump it and turn to your left. At the end of the fence, in the corner of the yard, you will see a disused greenhouse that hasn’t held any plants, at least, not plants kept deliberately. Instead, it’s full of rusting bikes and other garbage. And at the back, a spray-bottle that remains full despite how long it’s gone untouched.
The bottle cannot be removed from the room for too long without losing its potency. But it’s easy to get at least a good day’s use of it. Anything sprayed with the bottle will be covered, in moments, with growth: vines, grass, fungus, flowers, whatever’s nearest that could most conceivably cover whatever’s sprayed. Slowly, the plants will grow into whatever’s beneath them, consuming it regardless of what it is.
Not even They are proofed against it, but the bottle’s time limit and the long weeks it takes to regain its strength make it a limited weapon at best.