Transformers...Again

What the fork is a Transformer? I watched the cartoon as a kid, I'm 4 movies deep, and I have no idea what these things are. They're aliens from planet Cybertron. Great! But they're also robots. Robots that can change into cars and planes and split. And they have creators: ancient beings that want to destroy them...like Prometheus. The more I watch these movies, the more I wonder if a) story ideas are transcribed in drug-fueled staff meetings or b) scripts are generated randomly by a Micheal Bay super computer. A sexy computer with tight pants and pouting lips.