There is something unsettling about the idea of a living hat, yet it proved to be one of the best additions to Buy Now  when it released in October. As a new friend of Mario’s, Cappy turned out to be equal parts adorable and helpful. Was this all a ploy to lower Mario’s defenses? As it turns out, a newly discovered glitch allows Cappy to make the titular character disappear.

According to a gameplay clip from Twitter user DefinitivNichtSacha (via Eurogamer), Cappy’s ability to kill off Mario appears to be accidental. In order to perform the glitch, Super Mario Odyssey needs to be running in two-player mode. After Mario uses Cappy to capture a Piranha Plant, which can only be done by feeding it a rock first, Cappy can then attack the plant, killing it and Mario in one fell swoop.

I found a glitch in #SuperMarioOdyssey‘s 2 Player-mode that lets Cappy kill Mario when capturing a Piranha Plant. #NintendoSwitch pic.twitter.com/SzM3bMjZEN

— DefinitivNichtSascha (@NichtSascha) November 13, 2017

As players will discover, this sort of locks the game. Mario doesn’t exactly die but he does cease to exist. Cappy can still fly around and return to where Mario exists in spirit, but Mario can no longer progress. In order to continue, players can simply fast travel to a nearby flagpost to see their beloved hero reincarnated.

Nintendo has not mentioned the issue and it doesn’t appear to break the game, but it will likely be patched out in future updates. Anyone interested in recreating the glitch should try it before it’s too late.

Super Mario Odyssey launched on October 27 with almost universal praise, going on to sell more than 2 million units in three days. In our review, we praised its well-polished gameplay with tons of nods to past games. One modder enjoyed the new hat mechanics so much that they retroactively added them to Super Mario 64. While it is clear that the game was not intended for Cappy, his powers make it easy to take out certain enemies and reach difficult areas like the top of Peach’s castle.