Music is an integral part of The Legend of Zelda, but it’s also typically a strong point across most of Nintendo’s games. You need only glance at the staggering setlist of Super Smash Bros. Ultimate, a rich compilation of the greatest music in Nintendo history, to realize just how incredible Nintendo’s ability to compose soundtracks truly is.

So, if you’re going to use a song to test a new game in development, it stands to reason that you might as well make it a great one.

Zelda’s Study is a series where we examine the history of The Legend of Zelda to bring you some fascinating (or just plain weird) trivia. In our studies, we’ll explore each game’s development, curiosities within the rich lore of the franchise, and the impact it has had on our culture. From time to time, we’ll also look at Nintendo’s past to unearth some facts about our favorite company.

Hidden in the code of Four Swords Adventures, there is an audio file titled “smw.ast.” It is the same track used in the Special World in the SNES classic Super Mario World.

The Cutting Room Floor notes, “Since all of the game’s actual music is sequenced, this wouldn’t fit anywhere in the game.”

It was very likely used simply for testing purposes, and it’s no wonder; I’m certainly not alone in getting this infectiously catchy tune in my head on a regular basis since I first heard it in the ’90s. I always find it endearing when Nintendo borrow assets from their existing games in order to develop a new one.

If you’d like to listen to the track, you can do so here.

If you want more of the portly plumber tangling with the world of Zelda, he was featured in last week’s Art Gallery in celebration of Mario Day.