Firefox Hides Playable Snake Game Behind Address Bar Calculator Trick

A Reddit user accidentally found a playable Snake game buried inside Firefox’s address bar while doing quick arithmetic, setting off a wave of testing across the browser’s subreddit.

The user, posting under the handle TheMostRandomGamer, said they typed a multiplication into the address bar using Firefox’s built-in calculator shortcut — a feature that evaluates math expressions directly in the search bar — and triggered a game instead.

How the Easter Egg Works

The user typed 25×6, which returned 150. A small Firefox logo then appeared beside the answer. Clicking it launched a retro Snake-style game inside a pop-up window.

The trigger is not the specific equation. Any calculation that produces exactly 150 unlocks the game.

PiunikaWeb, which first reported the discovery, confirmed the following equations all launched Snake: 1×150, 2×75, 3×50, 5×30, 6×25, and 10×15.

There is one precise requirement: users must click the small Firefox icon that appears next to the calculated result in the address bar suggestions. Clicking elsewhere in the suggestion list does nothing.

The Game Itself

The Snake game uses standard controls — arrow keys move the snake — and carries Firefox branding inside the interface. It runs as a stripped-down version of the classic arcade format.

some users in the Reddit thread reported input lag. Others said the Firefox icon did not appear in their version of the browser at all, suggesting the Easter egg — a term for a hidden feature intentionally embedded by developers — may not be active across all Firefox installations or versions.

Mozilla Has Not Acknowledged It

Mozilla has not publicly documented the feature. Several long-time Firefox users in the thread said they had no knowledge of it before the post surfaced.

The reason 150 serves as the trigger remains unknown. PiunikaWeb speculated the game may have shipped quietly with Firefox version 150, but acknowledged that is unconfirmed.

Mozilla did not immediately respond to a request for comment.

Firefox is developed by the Mozilla Foundation, a nonprofit organization based in San Francisco. StatCounter data puts Firefox’s global desktop browser market share at roughly 6% as of early 2025, trailing Google Chrome and Apple’s Safari.