https://play.google.com/store/apps/details?id=com.miniclip.plagueinc -- Android
https://itunes.apple.com/us/app/plague-inc./id525818839?mt=8 -- Iphone
http://www.ndemiccreations.com/ -- Dev site
This game allows you to create a disease and then modify its DNA to wipe out the world. They bill themselves as a 'hyper-realistic simulation'. Note that it also works to track ideologies or memes. Really fascinating stuff.
K.