This is the second part of a four-part story:
Bob and Phong discuss the thing that came out of Hex's mirror - it is either gone or not detectable by Phong's sensors. Since it attacked Hex first, maybe it goes for viruses. "Megabyte," croaks Hexadecimal. "That's right," says Bob. "No, Megabyte!". The virus in question is standing right behind Bob, colored completely black. It shows exceptional strength by knocking Bob for a loop. Then it picks up Hexadecimal, and its hands start passing through her body. Glitch's wide-field energy beam knocks the evil MB away, but when Bob has Glitch fetch the car, MB returns. HD tries to hold him back with orange fireballs, but she is too weak to keep it up. Just then Dot swings by and picks up the black one with a Data Crane. MB tries to take over the vehicle by infecting it (turning it blue) but Dot is prepared and jettisons the gripper.
While driving Hex to Lost Angles, Bob demands answers. He wants to know why HD and MB were merging. She explains that they are from the same viral strain. "The same family?" "Much worse than that, he is my brother!". Their fighting is just sibling rivalry. "What will happen if you join?" "The next generation! Ha ha ha..." Just then Megabyte shows up, rips Hex from the car, and plunges to the street below. After the column of fire dissipates, a combination creature is visible. It has MB's skull, eyes, shoulders, and joints, but HD's facemask, arms, and breastplate. The right hand has long sharp claws (like Freddie Krueger from "Nightmare on Elm Street"). Hanging off the back of its red spinal column are the black multifaceted tendrils of the creature from the Web.
Bob: "I am Guardian 452. State your function."
It: "I am become Gigabyte, destroyer of systems".
Bob tries using Glitch as a wide-field energy beam again, but Gigabyte simply absorbs it. Dot swoops in, but her Data Crane gets cut to pieces. The creature is stronger than Megabyte, but so far has not used any of Hexadecimal's higher functions. It appears to have the potential ability to create its own portal to the Supercomputer. Bob tells Phong to shut down the city, then he sends out a distress call, stating that they are fighting a Class-5 (energy absorbing) virus. Bob and Dot try to get as far away as possible before their zip-boards fail.
Trapped in a dark alley, Gigabyte demands that Bob hand over his Guardian key tool. Bob has Glitch fly away, and just before GB puts his claws into our hero, something comes in and chops off Gigabyte's arm. It's Mouse, "Did you miss me?" Her ship is not affected by the city powerdown. Phong is not prepared to allow Mouse in the Principal Office, but Mouse hacks through its defenses.
Out on the streets of Mainframe, Gigabyte is sucking energy out of binomes, including a One dressed up as Indiana Jones. It continues toward the Principal Office, but the shield there won't last long once GB starts absorbing the energy from it. Bob has a plan to overload Gigabyte with an energy surge from a tear. Mouse and Dot are sent out to capture a tear while Bob tries to hold GB back with the primitive weapons available in Phong's armory. Bob is in black, with a black cheek guard that makes him look like Gambit, one of the X-Men. Hack and Slash show up, and do a good job of assisting Bob. After GB is lured to Floating Point Park, Phong releases the sector so that it is far away from the city.
Meanwhile, Dot keeps the ship steady as Mouse uses a video game console to build an icosahedron around the tear. A sudden surge sends Mouse flying - Dot flies the ship and catches her before Mouse falls into the Energy Sea. Bob has things under control until Hack (the red one) gets too close to Gigabyte and gets all his energy drained. Slash (the blue one) is so angry that he knocks Gigabyte all the way back to Mainframe, ruining Bob's plan. With Hack's energy, Gigabyte is able to fly over the moat and attack the Principal Office directly. The last line of defense is two small sprites; a girl, a boy, and his dog. Frisket's great strength is no match for Gigabyte, but his action delays GB until Bob and the tear can arrive. The tear overwhelms Gigabyte with too much power. Glitch becomes a splitter, and separates the monster into three portals (Hexadecimal, Megabyte, and the unknown black thing).
Mouse uses her wrist band, and determines that the unknown presence is still in Mainframe. [Why was Mouse prepared to track the thing?]