Bizarre music playing- “IRV 2.0 Single File Edition”

I was using the lottery machine when some weird audio started playing, consisting of thunder crashes and other eerie noises Ike a horror movie soundtrack. It kept playing under the normal music throughout the app for several minutes and even played a bit after I exited the app. My phone’s lock screen displayed the flying gorilla app and said it was playing “IRV 2.0 Single File Edition”. Soon after it stopped and I haven’t heard it since. 

Not really a complaint but does anyone know what this was/what triggered it to start playing? The gold diamond maybe?