Mizaru was an Arachnichimp crime lord and was the main cause of the near extinction of the Arachnichimp species.
Mizaru looks like most Arachnichimps, but he appears to be overweight, almost the same shape as Ultimate Spidermonkey.
Ben 10: Ultimate Alien
Mizaru first appeared in "Simian Says". After escaping a Highbreed ship, Simian makes a deal with him and Mizaru was infected by a Xenocyte Queen. At first, he struggled with the queen but retained his free will. From there, he started infecting all Arachnichimps he could find. After a battle with Ultimate Spidermonkey, he is defeated and the rest of the world is rid of the Xenocytes. He swears to make his revenge on Ben and his team. However, he was eaten by a Root Shark.