At what point does high-tempo dance music cease to be dance music at all? Well, for most people, it’s probably around 200 BPM or so—but for a courageous (or foolhardy) few, even that’s not enough. For them, there’s the brutal, 250-BPM-and-up world of speedcore, not to mention even more brutal offshoots such as splittercore and extratone. At this music’s most severe, the beats cease to function as rhythm at all, serving more as a vibratory gateway into a frightening quantum realm; it’s the kind of music that makes the heaviest of metal sound like a kiddie-show theme. As one commenter on this video of unknown provenance states, “That's what you see when you fall into hell.”