Part 1: Experiment 8.7
The hacker has Experiment 8.7. Now he has 9.1 as well, which adds creepypasta. Kyle has to warn everyone or we are all doomed.
Rikki was a creepypasta fan. He knew a lot of them. This may be why he has taken down first. He was playing normally, until he turned around and saw Herobrine. He freaked out and ran into his house, only to find Entity_303 and Null. He retreated into his mine but Daylight Owl, TheRedSteve and yraniB were waiting. At this point he felt like he was going to die. All six of them surrounded him. Frost Girl, Behemoth and Gourmand them. More and more creepypasta crowded around - Error 404, greenSteve, you name it - until Experiment 8.7 lowered from the ceiling and Rikki, in real life, had a panic attack. He quickly went into the Creepypasta Discord and found Kyle. They tried to warn everyone but Jem, another boy, dismissed them.
Jem and the Multiplayer Invasion
Jem was playing Multiplayer, nothing would stop him! Until he, and over fifty other players, were slaughtered in the middle of a Mega Walls game. Jem realised that Kyle and Rikki were right and quickly Skyped his friends Billy and Andy. The five of them met on Discord and tried to find a way to stop Experiment 9.1 but couldn't. Then, Josiah joined the chat. He introduced himself and told them that there was one way to stop the creepypasta - with another experiment. He showed them Experiment 2.10 and they realised what he was saying. They had to fight fire with fire... But first, they need to summon Experiment 9.1, for a third of Minecraft's players have quit already!