Mesoquack is a villain in Aftermath 2 that appears fairly early on in the story. He is actually the other half of Mesonak that remained behind when the original was split off. He carries a glowing electrically charged sword with a lightish-blue hue, similar to Mesonaks.
Thousands of years ago, when Mesonak was first created as a sentient Xenon-infused piece of machinery by TUG, he was split in two by a failed attempt at cloning. The first half, which would come to join the Toa Zehvor later on, managed to escape. The other half was left captured and enslaved, and eventually sent on suicide missions with a chip implanted on his back that would explode and kill him if he strayed from the mission. He stayed this way for thousands of years, until he was sent to The Void to assist a struggling group of revolutionaries. Unwillingly, this half of Mesonak became allies with this group, lead by PurpleBouncy, and helpd them gain supplies and resources until he ran across a rogue Toa Zehvor named Assassin. The two fought, Assassin compelled by a desire to destroy someone who he did not trust, and "Mesonak" by the chip on his back(he had been ordered by TUG to kill Assassin or die trying), until a blast from one of Assassin's cannons shattered the chip on Mesonak's back. Realizing that he was free, and that he had little hope of surviving the battle, Mesonak escaped, after being called a "cowardly vigilante" by Assassin.
When "Vigilante" appears in Aftermath 2, he is far more powerful than his last battle against Assassin due to months of theft and looting of The Center's test environments, and is now fully focused on the goal of getting revenge on TUG. In hopes of finding a way out of the Void, he attacks Bouncy's friends and kills them all, but does not find a way to escape the planet. Realizing that he now will be targeted by Bouncy, he quickly summons Bouncy to a meeting on Highrise Tower, a huge tower in the middle of one of the test environments, intending to kill him before he can find out. However, Bouncy sends his new friend, MT, instead, and Vigilante is disgusted by the fact that his plan did not work. He quickly realizes that MT is a being of power, and that killing him would likely work to his advantage in the long run. He battles MT on the very top of Highrise Tower, and, after a long, drawn out fight, finally gets the upper hand by stunning the Zehvor leader with lightning and knocking him unconscious during the immobilizing after-effects. However, he is interrupted by Levacius and Mesonak, and kicks MT off the top of the tower by accident. Vigilante, recognizing Mesonak as his long lost twin, challenges him to a fight. Mesonak laughs the challenge off after hearing that Vigilante goes by "Mesonak" as well, referring to Vigilante as "Mesoquack." The three battle, and Mesoquack takes down his cocky twin easily before being forced to retreat by the threat of a lightning nova blast from Levacius.