After bones start spawning, wait 3 seconds and you can press space to attack. Double click the flag so it syncs and doesn't lag. Since this contest never ended, well..... I haven't animated in a while, so this isn't as good as some of my animations.
Sprites by @FrostBurn200. Animation by me. Music by me. Other code by me. Bone sprites by Toby fox. Sans expressions by me. Papyrus sprite by toby fox