Parappa really puts the fast in fast food.
This is a really odd bug that makes Parappa (And any other actions that would following him, like PB dancing or the crowd singing in the final party) not move and go silent, while still awarding points and switching from Good and Cool. I'm not too sure how it triggers yet since I just found it, but I believe it happens when you spam too many button presses in an overall stage and the replay just can't keep track of them all. To maximize this, I did the trick to get the highest difficulty (Holding R3 and tilting it down slightly while selecting Play Stage) so that there would be the maximum amount of playable lines, and while in Cool mode, I just repeatedly spammed buttons to get out of it. It's really tricky and practically useless, since you need to consistently get in and out of Cool mode practically every line, and it only shows up in replays, but maybe you'll find it entertaining.