Mozilla sneaked a browser plugin that promotes Mr. Robot into Firefox—and managed to piss off a bunch of its privacy-conscious users in the process.

The extension, called Looking Glass, is intended to promote an augmented reality game to "further your immersion into the Mr. Robot universe," according to Mozilla. It was automatically added to Firefox users' browsers this week with no explanation except the cryptic message, "MY REALITY IS JUST DIFFERENT THAN YOURS," prompting users to worry on Reddit that they'd been hit with spyware.

"I have no idea what it is or where it came from. I freaked out a bit and uninstalled it immediately," one user wrote on Reddit.

Without an explanation included with the extension, users were left digging around in the code for Looking Glass to find answers. Looking Glass was updated for some users today with a description that explains the connection to Mr. Robot and lets users know that the extension won't activate without explicit opt-in.