One of Pokémon Legends: Z‑A’s key items may have first appeared 12 years ago in unreleased X and Y data, suggesting a Mega Evolution was planned for over a decade

Although Mega Zygarde is new to Legends: Z-A, fans speculate the concept may have been planned long ago. Bulbapedia’s Twitter account pointed out an unused key item found in X and Y called the Common Stone. That unreleased item’s description reads: “A perfectly normal stone that might appear valuable to some. It’s all in the eye of the beholder,” which sounds remarkably similar to Z-A’s Pebble.

Did they plan Mega Zygarde all this time?In X and Y, there’s an unused Key Item called the Common Stone – a completely ordinary rock with no apparent purpose… pic.twitter.com/4fbEnNtIN3November 9, 2025

“A perfectly normal stone,” indeed — the Common Stone’s description closely mirrors the Pebble’s wording. It’s also reminiscent of the Intriguing Stone key item from Omega Ruby and Alpha Sapphire, which later turned out to be a Mega Stone for Pidgeot. Hard to call that merely coincidence.

Game Freak has a history of embedding subtle hints in earlier titles that point to future developments. The Strange Souvenir, added in Generation VI, was initially described as “an ornament depicting a Pokémon that is venerated as a protector in some region far from Kalos,” and was later interpreted as a teaser for the Alola region in the following generation.

Whether the Pebble is another deliberate breadcrumb or simply a happy accident remains uncertain — the Common Stone was never officially distributed — but it’s an intriguing possibility. Perhaps Mega Zygarde was intended sooner, and returning to Kalos in Legends: Z-A provided the perfect opportunity to realize it.

You can read our Pokemon Legends: Z-A review if you haven’t picked up the game yet, or consult our Pokemon Legends: Z-A tips for helpful starting advice.