Easy, computer viruses are interchange so that. Then I’ll use a Stargate to get home.

What can I do? I’m just one man. Why should they listen to me?

Give them all the intel I can remember to make the destruction more effective.

Infiltrate the project and jib the numbers so that they end up destroying Oirth instead.

On the opposite side imagine waking up tomorrow with full memories as an alien species, but knowing full well that parts of humanity are planning on their destruction.

You are still “just” you. If you tried to explain it people would probably just think you are crazy.

I feel like a “know your enemy” kind of role where you try and educate people about this other species existence and relate their experiences to each other and hopefully find a synergistic point

It depends on why they want to destroy Earth, but honestly I’d probably just live my alien life and think that the human life I thought I had was some kind of weird déjà vu.

Depends on what you mean by “destroy Earth”.

If they actually wanted to physically destroy the entire Earth, I may have to do something to stop them, cuz I think the natural world is beautiful.

If they specifically wanted to destroy humanity, I’d go out of my way to help them, as that would actually help preserve the natural world and eliminate the threat of a violent species colonizing the galaxy.

Depends. Are they building a hyperspatial express route?

Give them tips

I feel this strongly depends on which circles the alien grows.

For example: You find your species is going to extinct whales/pollute the seas/commit genocide in Gaza. What are you able to do to prevent that?

Depends on the reason they (us?) have to destroy Earth. And is it Earth or humanity the target? If it’s Earth there has to be a really good reason. If it’s humanity… maybe it’s the dark forest. But even in the dark forest scenario I’d try to make a case for humanity. After all I could be a bridge¹.

¹ I hope they don’t burn bridges.

You all are forgetting that cats live on this planet too!

I mean, kinda hard to say without context. Are these aliens even compassionate? How smart are they and what’s the reason for blowing it up? etc.

If I can’t argue how fucking stupid it is to destroy the entire planet, I might become a fervent earth-destroying zealot and undermine their efforts through my utter incompetence.

Hand me that illudium Q-36 explosive space modulator, will you?

I’ll take a slightly different angle.

Assuming that my new homeworld is inherently aggressive and conquest-oriented, a make the case to spare Earth for the time being. Instead, begin a program of infiltrating and integrating into human societies with the goal of influencing technical and social advancement to make them as aggressive and warlike as us. It would not be difficult to do given humanities natural proclivities. When the time is right, introduce ourselves, form an alliance, and use them as front-line cannon fodder for future conquests.

“Reincarnated”, so I’m fully one of them. I grew up in the culture, and their history is my history now.

I do nothing, I don’t care about the past.