Spores... THAT Was your answer to my question last time?
It was only chapter 2! Why'd you rush it!?
Now I can understand you using spores (have to keep with the plant theme here) but having an instant change like that was too fast, poison joke takes a night to take effect but having a potted plant figuratively sneeze and instantly cover the world in anthro powder is too Mary sue ish.
A good route would have been a gradual change, like waiting for plunder to be tree sized, then it would be believably possible for him to release spores through the years to cover the world.
But that's just how I would have guessed how this would have worked.

8194073 1. he's been around a week seeing this.
2. this isn't poison joke and was intentionally made by him.
3. Celestia and Luna were right next to him when it happened, meaning they got more of it.

Question: Update?

8288840
answer: happening soon, also.

8194073
sorry, you were kinda right with this sort of thing... it did seem too fast, so I'm going to rework the situation in the next chapter, but I will still have Luna and Celestia's transformation stick to it being instant for them. okay?

8477709
That would make sense with them being in extremely close proximity, as well as being in a semi enclosed area, that would force the speed of their mutation.
Sorry if I came off as a bit harsh last time. I've had time to reflect on it and realized I came off as a know it all. This is YOUR story, I'm just reading it as well as commenting.

Me think story interesting. Need read more off. when next chapter?

Why didn't I read this sooner? It's hilarious! Plunder is freaking amazing!

Best. Plant. EVER!!!

Wooooow..........

Oooookay then............

I did not expect this.................................