Prefabs are altered during playmode?

Alright, so I have a prefab in my scene. It has custom monobehavior script attached.
During playmode (editor), the prefab has some values changed to this script.
The object also gets deactivated during the process.

Normally, you'd expect all these changes to revert once I stop testing in playmode.
Problem: they don't. I have no idea idea why this happens, or what in my code might cause this.

So... does anyone have any idea why my prefabs get saved during playtime, and how I can prevent this from happening? Thanks in advance!

 

Prefabs are an asset. So if you make changes directly to the asset, they will persist. It's only scene objects that revert.

 

Really? Can't believe I didn't know that. Thank you so much.

Question. I want to have prefabs in order to quickly edit objects over multiple scenes.
I have a BGM prefab for instance - if I change the music, I want to edit the BGM prefab and click apply without editing multiple scenes.

But I also want to test the game without actually altering them.
What's the usual way to achieve this?

 

You can create a scene object that everything references, and keep it around with DontDestroyOnLoad.

 

Thanks for the tip!