Plausible considering canon tech? I'm thinking along the lines of Transformers, Robotech, Macross, The Viking from Starcraft 2, etc. Stuff that is at one point a vehicle and the next a combat robot and even a combination of the two. I have no background in engineering or mechanics. Just asking.
—"And yet, across the gulf of space, minds immeasurably superior to ours regarded this Earth with envious eyes. And slowly, and surely, they drew their plans against us."