Okay Here is how it works:

There are infected members on PMC, who are Spam Zombies. Uprooting any of their wallposts will make you a victim and they will then spam you. Commenting on any of their creations/posts will infect you. Spam zombies may also spam random users. You are then a Spam Zombie, and must spam all users (or users of your choice) and try to infect them as well. If they comment or reply, you have to tell them that they have been infected and provide a link to this account. If they updoot your posts, you have the choice to spam them. (I suggest you do, since (duh) you're a SPAM zombie.