Mizaru

Mizaru was an Arachnichimp crime lord and was the cause of the near extinction of Arachnichimps.

Appearance
He appears to be and overweight version of his species. When he was taken over by the Queen Xenocyte, he retained full control.

Powers and Abilities
Because he's an Arachnichimp, he has all of Spidermonkey's abilites.

Ben 10: Ultimate Alien
Apparently after escaping a highbreed ship Simiam unknowingly makes a deal with Mizaru and is soon infected by the Xenocyte. At first he struggled with the queen over power and retained his free will. From there he will soon start infecting all of his subjects and eventually the entire world except for a family of 3. After a battle with Ben (as Ultimate Spidermonkey, he is defeated and the rest of the world is rid of the Xenocytes. He swears to make his revenge, but he is soon killed and eaten by an underground monster.

Trivia

 * He's the first adult version of his species to be seen.