Sonic Mania has an Easter Egg that only the most diehard fans will ever notice, and that’s incredible.

Back in July of 2016, Sega was trying to drum up hype for the 25th anniversary of the beloved and eternally bruised Sonic franchise. The festivities included a 25th birthday party for Sonic the Hedgehog at San Diego Comic-Con.

The event was livestreamed, and it included all sorts of stuff. It even offered some Sonic Mania footage. The thing about the stream that irked fans the most, though? It included this awful audio feedback throughout the show, and the whistling, buzzing and whirring was constant.

Here is a supercut (with some NSFW language) from Jim Sterling. The buzz starts around the 50-second mark.

Okay, so! One eagle-eared (Is that a thing? It is now!) spotted a moment in Sonic Mania where, if our heroes stand in front of a screen, you can actually hear the exact same feedback sound that marred the livestream. Seriously. It was even confirmed by Brad Flic, a designer for Sonic Mania.

This is incredible, and it somehow makes me want to play Sonic Mania even more. Kudos.