Samsung didn't have many surprises left to announce with its thoroughly leaked new Galaxy S7 phones, so it decided to spring Facebook chief Mark Zuckerberg on an unsuspecting crowd. What Samsung itself might not have suspected, however, was just how raucous and frenetic the reaction would be.

The setup was great: journalists were invited to watch a virtual reality demo using Samsung's Gear VR headsets, and when the time came to remove them, there was Mark Zuckerberg standing in the middle of the stage, wearing his familiar gray T-shirt. Cue a moment of confused gasps of excitement, followed by an escalating stampede of journalists and photographers toward the stage. Zuckerberg was there to talk up Facebook and Samsung's VR partnership, but his words went mostly unheard as everyone was too busy trying to capture an image of him. It was the tech celebrity equivalent of Bieber mania. And it was a little bit scary. Or maybe a lot, since Zuckerberg walked off the stage with sweat patches under his arms. In any case, the desired outcome of drumming up hype was achieved.

Right now, just over my left shoulder, an Australian TV presenter is doing a segment for his home network on the press event and the only thing he's talking about is the chaos incited by the Facebook CEO's appearance. The new Galaxy S7 and S7 Edge are amazing, wonderfully advanced devices, but today they were overshadowed by the towering figure of Mark Zuckerberg. Unexpected in more ways than one.

Update, February 22nd: The following morning's TV and radio broadcasts here in Barcelona both led with Mark Zuckerberg's name. As big a show as MWC is, all the companies actually exhibiting new products and making big announcements were relegated to second place behind the Facebook chief's guest appearance.

Check out more from Mobile World Congress, including the debut of Samsung's Galaxy S7 and S7 Edge: