It's an in-joke.
Fixed an issue where the image didn't load properly.
Updated image, scripts, music, and fixed some bugs.
Riolu can only run across your screen if you're on a website, not the new tab screen or web store. Also make sure photobucket is unblocked.
Things will make more sense if you watch this video. https://www.youtube.com/watch?v=cMGerbYf2oY
A "kool" little dude will do a quick run across your screen.