As a fan of drumming, you're probably one of the millions who have seen this. But for anybody who hasn't, here's a fun video showing how complicated drumming can be with a live performance by someone whose nickname is "The Octopus".
While the entire video is fun, the link is cued up to a place where there's a lot going on, but it's slow enough that you can kind of see what he's doing. Watch his knees to see what he's doing with pedals. Notice that his hands seem to be going in cycles, but there are subtle variations in the cycles.
At 8:54, strobe lights start up - that can't make it simpler to keep this focus. What he's doing looks essentially impossible to me, but I'm well aware that I don't know enough to understand just how insanely difficult it really is.