When people around the world logged into their Gmail accounts yesterday, some got a bit of a creepy surprise: an emoji skull and crossbones anchored in the right-hand corner of their screen. When users hovered over the skull, they saw ominous words like "Component Spy," "Channel Spy," and "Data Spy." The image was specific to particular accounts, and persisted across browsers, impacting users on Chrome, Firefox, and Edge.

The skull’s presence is ongoing, according to a Gmail Help Forum thread. One commenter noted that only one of his three Gmail accounts was impacted, and the image didn’t appear when logging on through Gmail’s HTML version. Theories ranged from the skull being a desperate ploy to find new Google developers to a not-so-covert form of spyware. But what kind of spyware would announce its own presence with such a spooky symbol?

As it turns out, the culprit is Google itself. The skull was produced by the company’s in-house debugger, which it uses to flag bugs in its code and email functionality. The skull is, well, a bug itself, or an error in the debugger.

When asked for a comment, Google replied to The Verge with this statement, or rather, state-meme.

So mystery solved, Gmail forum posters. Your email isn’t haunted or infected, or at least not yet.