I don't know what caused this, but it can probably be used more and/or made consistent.

There we go, because of your discover we can actually save 2min+ on undertale stage

All information of this glitch is here, also the kirby wrong warp: https://pastebin.com/YTCsciaN

Well, since we are talking about skips here, on the cthulhu fight if you reser after you awake the boss, it will cut the animation. Something similar happens on world 4, just reset after you press up to get on 3d mode