5 Sept 2017, 15:39

@andrew42 Originally, Ben was supposed to become Ben 10,000 at the age of 15. However, Derrick J. Wyatt changed that to the age of 20 over the stupid excuse of time constantly shifting. That's the when. As for the how, well, something tragic happened to Ben that affected him in a negative way and it's most likely related to Ben mutilating Vilgax. As for Max losing his arm, it was stated that he lost it during the Limax War so it's likely not related to Ben's transition into Ben 10,000. Have you ever seen or read DC's The Killing Joke. The Joker makes a point on how it could take just one bad day to make a normal person go insane (which is what happened to the Joker). Everyone has a breaking point and Ben reached his thus resulting in him becoming Ben 10,000. Of course, we never even got a chance to see what really happened because Cartoon Network would rather sell more Ben 10 merchandise than let the franchise fulfill its potential and opportunities.