Need Help Removing Permanent Mozilla Bot Attached to My Mac Home Screen

Help! I have tired to find support but no luck. A weird Mozzilla bot has attached to my Mac home screen and I can’t get rid of it. I can enlarge it but cannot move it or delete it. Attached is a screen shot. Any help is appreciated. Thank you.

It seems to have a Developer Tools toolbar along the bottom. Is it a browser window? Can you close it using Command+w?

Thank you! Your recommendation worked. Yes, the window did resemble a browser window.