What is this fingerprint bar on my phone? I've had this phone for a few months now.  During normal usage today, this thing suddenly appeared.  Tapping, long-pressing, swiping did nothing.  It persisted above everything, even the keyboard (as seen), until I rebooted.  Checking the running apps didn't show anything weird.

Anyone have any idea what it is or where it came from?
I don't know what it is, but I also just had it pop up an hour ago. As you said, persistent between apps and screens, but goes away on landscape orientation. I am on a Moto X Dev running Eclipse 4.4.2. 

Edit: It seems to be a feature added by the latest update from LastPass:
http://blog.lastpass.com/2014/04/lastpass-adds-biometric-security-on.html

Edit 2:I have just been stopping the floating fingerprint overlay service when it appears for now until last pass fixes the issue.