He doesn't kill people through the console. He tells you that he kills through the console, he gets you to step on evented invisible bricks or he makes a bit that, when touched, kills the player, then he makes the bit invisible via the editAppearance event. He also events it to walk to the nearest Player, and when it gets near the player and touches it, It kills the Player, but because the bot is invisible it gives the illusion it happens at random. As for chat spam, he can just go on a server without flood protection and keep hitting up. But all that silly conspiracy theorizing aside, I'm sure Fungusamoungus is a pro hacker who will one day HACK Badspot out of the developer position, then HACK the name from Blockland to Funguspalooza. Then finally he will HACK the price from $20 to $3000 a month, which obviously all gets wired to his super-secret Swiss bank account.
