In my indulgent search for the most schizophrenically edited, embarrassingly opaque anime-community-themed music video, I think the Ryuuseigun (medley of a ton of Nico Nico Douga meme songs)'s Chaos Version has the highest energy, most varied references, and most willingness to be sloppy of them all and is therefore best. You can cut into it at any moment and it'll be in-your-face total gibberish (that I, sadly, can parse). Every track is far removed from its original form.
https://www.youtube.com/watch?v=TUIBnElcLCM Also I was surprised by this a couple of minutes ago and it made my stomach lurch a little. I hadn't seen the left image for years and years. I was 13 and I saved it.