The Junkions
In 2005, the first Junkions arrived on Earth, seeing out the source of intercepted TV signals. Later that year, a massive planet-eater named Unicron attacked Cybertron, looking for something it called the Matrix. Not finding it, Unicron destroyed and consumed the planet, leaving only the Transformers on Earth and other planets alive. For the next several years, Unicron heralds have scoured the cosmos, looking for the Matrix.