And for God’s sake, leave it there, don’t bring it back home:
This little vine is a vampire plant.
It cannot produce chlorophyll on its own, so it’s wrapping itself around the petunias and sucking their chlorophyll. The petunias don’t actually become dodder, but the little fangs it puts into the petunias can grow into whole new plants if you tear it off the flowers. To handle an infestation, you’re supposed to pull it all up and prune below the place where the chlorophyll-suckers are, but with flowers, that means pulling the whole plant.
If you’re thinking “Well, I don’t have petunias,” think again:
Dodder is parasitic on a very wide variety of plants, including a number of agricultural and horticultural crop species, such as alfalfa, lespedeza, flax, clover, potatoes, chrysanthemum, dahlia, helenium, trumpet vine, ivy and petunias, and more.
This is the sort of plant which, had you read about it in a science-fiction novel, you’d dismiss as the author’s sick fantasy. The fact that it exists corroborates Brian J.’s theory: “There’s Always Something Worse In Nature.”