HummingBad is a potentially unwanted program on Android systems.
It will gain root access on your phone using a rootkit that exploits multiple security exploits. If the root fails, it will display a fake system update notification that tricks users into giving it many permissions.
After that, it will connect to a Yingmob server, it will do many malicious things such as install malicious apps, spy on the user, steal passwords, and more. It can also display unwanted ads, vibrate unexpectedly, or drain battery quickly.