Zenblock or Zen a blue alien who is constantly accompanied by Mem, whom he is virtually identical to physically apart from their coloring, teeth, and nose shape. Zen is the gruffer of the pair, but like Mem is largely unfamiliar with Earth culture. They were sent to Earth by the Benevolent Alliance to recruit warriors for the battle against the virus, but mistook the four children in paintball gear for soldiers. While he is often disparaging of the Noobs' skills-having been the one to give them their less-than flattering team name-he does have a soft spot for them, which led to him being assigned along with Mem to train the group. Zen is capable of disguising himself as an adult male human with brown hair who wears a blue outfit including a sweater vest, during which he employs the alias "Bob."