Mozilla/Firefox Browser lockup Scam - Is this new?

Just wondering if this is a new scam or not. Kind of weird, as it uses the Firefox Browser then puts a Microsoft Support number in the bottom right side. Weirdest thing was, it was on Firefox, but on my Apple MacBook computer. And I would call Microsoft why? LOL!

Can I see a picture so I can verify if it is or not?

Wish I could have got a snapshot, but it locked my Mac up completely, I had to restart it. But the background was the same orange color as the firefox logo, with a box in the lower right corner with a beige or tan background that said “Microsoft Support” and a phone number. It also said Mozilla Firefox at the beginning in larger text than the body.