Giant Killer Horses from Space

One of my more bizarre dreams....it was indeed about giant, killer horses from space. They arrived in ships that resembled the Millenium Falcon and were 2x or 3x the size of earth horses and instead of hooves had three metal "toes" on each foot. The trotted very smoothly, almost gliding, across the countryside. People were going to metal pens, areas surrounded by metal fencing, to escape from the horses. I wondered how this kept them safe because the horses could easily reach over the fences, but it did seem to keep the horses away. I wasn't able to get to safety in time and was running away from them through the countryside and trying to climb a tree to escape. I watched as one horse turned a car over and killed the people inside.