User blog comment:Matt Hadick/Ultimate Battle Final Round/@comment-3367060-20130709173742/@comment-4738647-20130709204240

Optimus isn't 30ft, get your facts straight, there are no official stats, a good guess is that he's between 20m and 30m based on his original official alt-mode and that's only assuming he can't change size, a technique employed by a lot of transformers including Optimus already. that is why his trailer disappears when he transforms into a robot.

Only four known metals are magnetic; iron, cobalt and nickel and their alloys such as steel and I doubt a member of an advanced alien civilisation capable of interstellar flight is made of them, I don't even think my own PC contains any of those metals except for screws whcih are there to make locking screwdrivers in easier and those aren't the bulk of the machine.

Optimus Prime has taken down the giant Devastator with the help of Megatron, he has access to the matrix of leadership which allowed him to cure an ENTIRE GALAXY of plague and allowed his temporary successor (as he did come back to life) to rip a planet-sized robot to shreds. And I'm pretty sure a Kaijuu (that's less threatening than the aforementioned events) rampaging counts as a darkest hour.