I'll be honest, I didn't notice this happening when the video was live. But as you can see, John Mueller is doing one of his webmaster hangouts in an open cafe at Google and at the 8:45 mark into the video, Gary Illyes sneaks in and then video bombs John.
You can see Gary sneak in on the video in the back left frame. Then, lucky for John, someone else begins talking and the large screen gets taken over by someone else. But you can see Gary right behind John making weird faces.
Here are more screen grabs:
Here is the video embed when it starts:
Rachel Costello noticed this and posted it on Twitter:
A powerful lesson: If you run a Google Webmaster Hangout or any other kind of video meeting in a public space, your coworkers will troll you without mercy. Well handled @JohnMu 🤣 https://t.co/4T0JfXPuGv pic.twitter.com/lERJraMqb1
— Rachel Costello (@rachellcostello) March 20, 2019
I think John was expecting worse:
They were threatening much worse :). (The lighting in that room looks terrible, and the microwave's "ping" was a bit unique :-))
— 🍌 John 🍌 (@JohnMu) March 20, 2019
Forum discussion at Twitter.