So why Earth?
It's the All Spark.
All Spark? What is that?
Well, they came here looking for some sort of cube-looking thing. Anyway, Mr. NBE-1 here, aka MEGATRON...
[glares at Simmons
That's what they call HIM... who's pretty much the harbinger of death, wants to use the cube to transform human technology to take over the universe. That's their plan.