It's an NFC Ring. With your help, the phone is now recognizing it - thanks!
I'm still curious about the verification code issue, though. To clarify, I launch the NFCRing unlock app, and the screen says:
NFC Ring One Time Verification
Verification Code: ___
I tried putting my email but leaving the verification code blank, but then clicking the button just takes me to the NFCRing site. I'm a bit confused on how/where to get the code.