Definition

An obscure instrumental layer hidden in the Undertale song "Megalovania" that only the most dedicated fans claim to hear, despite it technically being an organ and square wave, not a harp. It's become a weird badge of honor in the fandom—if you can hear THE HARP, you're part of the 33% elite. Basically, it's the audio equivalent of a Magic Eye poster for gaming nerds.

Example Usage

I've listened to Megalovania 500 times and I still can't hear THE HARP—am I even a real fan?

Source: Urban Dictionary (https://www.urbandictionary.com/define.php?term=THE%20HARP&defid=17101065)