Botania 344, Minecraft 1.11.

It's possible to skip the mob wave of the Gaia Guardian and end the fight a little early.

1. Fight the Gaia Guardian until it stops teleporting and the "mob wave" attack begins.
2. Throw a Splash Potion of Instant Health at the gaia guardian.
3. The mob wave ends (?)
4. Now the guardian is in a weird state - it's still levitating upwards and isn't teleporting, but it's not invincible anymore.
5. Whack the guardian a couple more times to end the fight.

Video: https://youtu.be/OBWaiS-qsiw (I did it in creative but I imagine it would also work in survival. I didn't record the first half of the fight because it was just terra blade whacks, nothing special there)