Size X

Size X is the confirmed main villain of the video game, Phineas and Ferb: The Threat to the Earth. He is a blue To'Kustar who conquers planets for a living.

Trivia

 * He looks like the Evil Waybig from Ben 10: Cosmic Destruction.
 * He is AdamGregory03's second character based off of a Ben 10 alien, the first being Tin'a KurN.