To answer the questions: The last thing I did before the fight was mess around in the fake peppino fight, doing that weird climb jump and then climb thing on walls, (that you can see at the start.) then I decided to fight pizzahead. I didn't have any mods installed. I cant really remember if I was pressing any buttons, but I probably would and I was just spamming buttons. I don't have any footage of it before hand, only those 30 seconds. Plus I did try to replicate it and I couldn't. Also some weird thing that happened later that might be related is that I was playing Crumbling tower of pizza, and when I collected the noise, it made a really weird sound that I've never heard before. It might be related as this was soon after but i don't know.

No, It was my first time going in to the fight on that day.

Ok, first, I was basically just playing pizza tower and messing around, until I decided to go into the Pizzahead fight, and it glitched through the opening cutscene without me pausing and restarting? Also, I HAVE NO IDEA HOW THIS HAPPENED. Secondly: I think it has something to do with the present box, as Peppino was still flying up when it started. Thirdly: here is a link to a video of the bug: (also sorry I'm too lazy to cut out the filler part, just go to 0:12 to see the glitch.)