Two people, brother and sister, stared with a blank sight of their shut eyes at the dark, lifeless laboratory in a dark, lifeless building, while inside a liquid-solid stereotypical to evil laboratories, were the building they were housed an evil laboratory, which it was not. One who, when depicted as messaging someone, would be a gray neutral face, the other one a white skull. One with the black scythe-shaped hair slowly gaining a zigzag shape, the other with purple hair which looked as if it was going to enclose itself within a wireframe cube within few years.
Dib and Gaz Membranes, the only two kids of a certain world-renowned scientist, were now dead at his hands, and he didn't know what precisely to do with them.
Their father was well-known throughout the Earth, and, as no other sentient life had been found elsewhere, the Solar System. He was practically the god of the planet. Without him, Earth would now be a military development planet belonging to some spanning empire somewhere unknown in the universe. But now it was known as the only civilization that survived as a single planet and wasn't touched by anyone.
But while the Professor could save the Earth, he could not save Dib and Gaz, and the following showed.
He first thought about simply reviving them. That would reverse everything as if it never happened, and would be a solution, but then Professor remembered how Dib always chased after anyone who even remotely resembled the paranormal and Gaz always had stuck in her game console... Game Slave 2? 3D? Pray Station? Professor didn't want to search his memories for the answer to know that simply resurrecting them won't work.
Then he was hit with an idea.
What if he somehow combined them, keeping only the personality traits that he favored and getting rid of those which wouldn't be as great for a person almost always near him, if not literally, then at least spiritually?
He thought it was just the perfect idea that a mad scientist would employ, even though Professor wasn't really a mad scientist, and went on the work.
First he sketched out how the idea would look on paper. Even though he wasn't a very good artist, Professor had something in mind. Someone with Dib's coal black hair spike going up and purple branches from it, well branching, like a tree or Gaz's haircut, with a trench coat that Dib had but purple and the... whatever Gaz's arms were covered with but blue, and their Pesterchum or whatever symbol would be somehow combined. As for the gender of this kid, the genes had to decide it.
Thinking that the result satisfied him, Professor sketched out how it would be done. He would need a DNA sample that worked out, then a teenager's body (he had quite remembered that when the car crash where Dib and Gaz died happened, Dib was 15 and Gaz was 14) that he would piece together from the new cells with this DNA, then the sketched out clothing and hair style, and then he could simply turn this horrible freak of a nature on and voila, the Professor has a child that loves him to the deepest degree. Again.
He first thought of the first part of a plan. When humans normally mate and have children, their chromosomes mix together and from them comes a new set of 46 chromosomes, that later are the driving force of the development of a new human. But here, in a laboratory, separate genes and the 97% of the DNA that is used nowhere can be mixed in any way, as long as the new set of 46 chromosomes that technically doesn't have "parents" yields a functional human without six fingers on each hand.
The Professor needed to either have an already developed process of mixing the genes in this way, or make him himself.
He went around searching first, since that was probably going to save some time, even though the process described above sounded like science fiction and the Professor was the only master of science fiction on Earth. And, as it turned out, the Internet wasn't helpful: there only was a "Descendant Generator" on MSPA Forums which combined the colors of the two given people. The Professor put in the colors that codified Dib and Gaz, and got an oddly dark blue as a result, and painted the designed symbol in this new color.
Then he started programming a gene mixer himself.
Dib's and Gaz's entire genetic code was known already. The Professor had decoded it practically when the kids were born. What was really the thing to it was figuring out what specifically which genes did. He had noted what personality traits of Dib and Gaz he favored and what he despised. Dib had a thing for making cool technology, just like the Professor himself, but was extremely paranoid and even had gotten in a couple of lawsuits that the Professor remembered. Gaz was fairly level-headed, but could easily become obsessed, a thing which never allowed her to do something satisfying that didn't relate to video games.
It was going to be a long endeavor, but the result would be worth it, Professor reminded himself, but had to pause on the project as someone else called him, again cluttering up his busy itinerary. For this project, he would need to reject as much meetings as he could, and instead publish his new project on the news with his faithful spokesman.
Author's idiotisms: Note that by "a horrible freak of nature" I don't mean "what will turn out from the mixture of Dib and Gaz's genes". By "a horrible freak of nature" I mean "a story combining the worst properties of the rivalries-on-top-of-each-other story Division of Doom and a trollfic probably made on crack, even though I don't smoke crack, Invader Zim: Born Again Christian Tie-In to Chapter 7".