A few days back, Google reCaptcha suddenly showed me a QR code and asked me to scan it with my mobile to "verify" I was human. I was taken aback, and at first thought my system / browser had some malware that was messing with the Captcha ...
(Apparently, this started appearing from last month - https://cybernews.com/privacy/google-qr-code-recaptcha-requi... ).