Deleted asset keeps coming back

Hi

Yesterday I downloaded a package from the asset store, saved my scene as a new scene and didn’t save the project itself.
Then I realized that it wasn’t what I was looking for, so I deleted it from unity.

And it keep coming back, even if I try restarting unity, witch is very annoying.

It added function to the editor and I suspect this is why it keep importing the assets, but since I’ve never changed the editor, I’m totally lost and afraid of making a big mistake.

Does someone have a clue of what I should do?

The newbie noobish noob that I’m thanks you a lot in advance!

Right click the folder and go to show in explorer. Then delete (or move) the actual file from the folder structure.