Just don't ask him to turn into Grey Matter when he's fighting a dragon. That’s just rude.
For nearly two decades, Ben Tennyson has been slapping down the Omnitrix and shouting, "It's Hero Time!" With a watch that contains over one million alien DNA samples, Ben has access to a staggering arsenal. But while Grey Matter is smart and Stinkfly is... sticky, some transformations are in a league of their own. who are ben tens strongest aliens
The answer is with full control . Later in the series (specifically the finale of Omniverse ), Ben finally masters Alien X. He convinces Bellicus and Serena to give him full control over the body. At that moment, Alien X stops being a liability and becomes the most powerful being ever shown in the franchise. He recreates the entire universe from scratch because the old one was destroyed. Just don't ask him to turn into Grey
The strongest alien is ? Getting colder. But while Grey Matter is smart and Stinkfly is