Board Thread:Ben 10 Discussion/@comment-35864512-20180707163021/@comment-1824169-20180713163508

It wasn't explained at all in-show. Any external explanation is just speculation.

I assume you're power scaling a la Dragon Ball Super's Super Saiyan God forms, which don't actually have powers comparable to Alien X's. SSJG can punch real good, but Alien X can do literally anything. That's his power.