This is how I've accurately felt when I've been in any caves while playing the broken script mod for Minecraft. The music you hear playing is from the mod, when this music starts, you get slowness, blindness, and feather falling (for some reason) applied to you. One singular time when this happened to me, I was banned from my world after this song played. Might've been from an entity I didn't see. And if so, it's probably that one monochrome Steve skin one.
