They look a bit like sunflowers, having large leaves and largish yellow flowers in abundance. They move in packs across the ground, their roots twitching and slithering as they are propelled at an astonishing pace. They are strong as well, capable of breaking the glass of car windows and denting its sheet metal.
I don't know what garnered their ire in my dream but they seemed more nuisance than danger at the time. That may be because I saw the pack of them coming from across a largish parking lot and was able to get into my car and escape in plenty of time. In close proximity I suspect they are more terrifying.