I've decided to answer my own challenge! So, without further ado, here is my brave attempt at a Death Note/Invader Zim crossover ficlet.
If You Give A Mouse A Cookie
"Hand it over."
"No! It's for Mr. Mousy!"
"I will not allow you to give it to the mouse."
"Mr. Mousy! Here!"
"Do not make me defenestrate you…"
Zim entered the house, closed the door behind him, and burst into a fit of maniacal laughter. "Perfect!" he exclaimed. "My plan is absolutely flawless! Finally, I shall be rid of that large-headed fellow and…" He trailed off, looking around, confused. "Where is GIR?"
Still pondering this mystery, he flushed himself into his underground base. Once there, he looked around again, hoping to find the pesky little robot. But instead of GIR, he found…
…an intruder! The human was taller and more intelligent-looking than any of the other earth scum he had come across, but was rather…odd. Dark circles under his eyes made him look haunted, and he was sitting on his heels, slowly eating a cookie.
"Who are you?" Zim demanded. "GIR! Intruder!"
The human looked at him for a moment before saying politely, "I am Ryuzaki. Are you the 'Zim' the robot spoke of?"
Zim glared suspiciously at him. "Where is GIR?"
Ryuzaki pointed off to the side, where a pile of metal that once was the hyperactive robot was sitting.
"GIR! What have you done to him?"
Ryuzaki finished off the cookie before answering. "Did you know, Zim, that if you give a mouse a cookie, he'll want a glass of milk?"
"What does that have to do with GIR?" Zim demanded angrily.
"Well, when you give the mouse a glass of milk, he'll acquire a thirst for human blood? That would make him a vampire."
Zim pondered this…perhaps he should give a mouse a cookie and unleash it on the filthy earth scum…
"And if he became a vampire, he would need to gather followers," Ryuzaki continued evenly. "And if he were to gather followers, they would all need more human blood."
Now Zim was really convinced that he should give a mouse a cookie…perhaps several mice…
"If that were to happen, then the president would send in the National Guard to protect the people. However, they would be overcome by the vampires."
"This is all wonderful," Zim interrupted, "but what does it have to do with what you did to GIR?"
"I am getting there," Ryuzaki said patiently. "As I was saying, if the National Guard were to be overcome by the vampires, then the president would be forced to issue a nuclear bomb, resulting in the United States being reduced to a nuclear wasteland."
Zim gulped. Scratch that idea…not even he could survive Earth's atomic weaponry.
"With the United States reduced to a nuclear wasteland, there would be no one to keep the world's nuclear arsenal in check, and nuclear war would break out sooner or later. All of humanity would be extinguished, as well as any extraterrestrials that may be here." Ryuzaki was silent a moment, watching Zim. Then, "And that, Zim, is why I disassembled your robot friend. He was trying to give a mouse a cookie."
Yayness! I know, not too good, but hey, it took place in the universe of Invader Zim! Anyway, disclaimer time. I don't own either Death Note or Zim, and that whole "If you give a mouse a cookie" thing was something my brother learned from a friend at school. Not mine, but U haven't a clue where it originated. Anyway, hope you enjoyed!
