I made a short version of an undyne fight FOR ONCE A NO HIT RUN IS POSSIBLE IN SOME WAY. You have invincibility frames! Arrows to point at direction Block The spears (Cyan arrows) by pointing at them. If you let the 3 first spears hit you, undyne will be annoyed by your stupidity, TRY IT OUT!
Thanks to Undertale and other things :P HUGE THANKS FOR YOUTUBER SWORDZA OFFICIAL FOR PLAYING MY GAMES ON HIS CHANNEL, Check him out :D Fixed the invincibility frames