Invasive Vine (Kudzu)

The sniffer needs more plants: What if one of the ancient seeds it can dig up is a terrible risk to the overworld.

I am imagining a flowering vine a bit like Kudzu. In Minecraft, the vine would be made of a tangle-of-vines block which could grow additional tangles in adjacent spaces. It would be unable to grow taller than 2 tall on its own, but could climb walls and tree trunks.

Creatures would be able to move through the tangle-of-vines blocks as if they were scaffolding, but with a slightly reduced movement speed. 

The tangle-of-vines blocks could occasionally generate flowers, which then 'pop', firing seeds as if fired from a dispenser. The seeds would be able to slightly hurt a player or creature. If left on dirt or dirt variants, maybe even on gravel, these seeds would be able to plant themselves. 

Possibly the tangle-of-vines blocks would be able to replace leaf blocks.

Possibly the tangle-of-vine blocks would have radically different colors when grown in different biomes and dimensions, and could be grown in both the Nether and End. 

The vines would make the environmental stability of the overworld feel more precious, and would look amazing as they spread slowly across a jungle and into a forest, slowing down as they cross the plains towards your little farming base.