That makes Grey Matter his least favorite of the original Ben 10 aliens. This alien form comes from the Galvan — a 6-inch-tall, physically feeble species that is also gifted with super-intelligence.

The premiere of Ben 10 makes its U.S. debut Monday, April 10 at 5 p.m. (ET/PT) on Cartoon Network, but fans can also watch the episode today on the Emmy Award-winning Cartoon Network app. Be sure ...