Imagine a marathon race in which out of the hundreds to thousands of participants, you controlled not one, not two, but upwards of fifty runners in an attempt to make them all finish as high as possible.
Or, imagine this: You are a lone zombie in a big marathon race with thousands of participants. The goal is to try to infect as many other people as you can (turning them into more zombies under your control), and to have the resulting zombie horde finish as high in the leaderboards as you can.