# Google’s Pac-Man doodle exposed a Firefox extension’s hidden browsing behaviour

- URL: https://talkfuse.com/story/chap-who-coded-googles-pac-man-clone-reveals-how-the-game-freaked-out-firefox/
- Published: 2026-11-02T06:05:39+00:00
- Updated: 2026-11-02T07:47:31+00:00
- Original publisher: The Register
- Original article: https://www.theregister.com/personal-tech/2026/11/02/chap-who-coded-googles-pac-man-clone-reveals-how-the-game-freaked-out-firefox/5306879
- Topics: Software

## Key points

- Google’s Pac-Man Doodle unexpectedly played sounds for some Firefox users.
- CoolPreviews secretly opened Google’s homepage in the background.
- A mute button and click requirement fixed the problem.

## Summary

Marcin Wichary has recounted how Google’s 2010 Pac-Man Doodle unexpectedly made computers used by some Firefox users play sounds in the background. The incident showed how a design decision that seemed harmless on Google’s homepage could affect people through the way browser extensions opened pages invisibly.

For Pac-Man’s 30th anniversary, Wichary built a playable logo maze shaped around the letters in GOOGLE, with music and sound effects. Google set it to start after ten seconds of inactivity, but Firefox’s CoolPreviews extension quietly opened Google’s homepage when the browser launched. Wichary added a mute button and required a click to start the game, stopping the extension from triggering the sounds; he says few ordinary visitors were affected.

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