Gravity Falls Weirdmageddon 3 - Bills Backwards Message

Thanks to Chaotic Chris for figuring out the message, and TDCC1721 for figuring out the letters at the beginning! I could only make out the part about ancient powers and ’I may return’ on my own. So I don’t see anyone else having uploaded this yet, figured I might as well. I don’t have a fancy video editor that can reverse video so I did the lazy version and reversed just the audio with audacity and used a picture.