An application will automatically reinstalled from mac app store after uninstallation

It's so weird that I don't know how to explain it.

Blackmagic Disk Speed Test is the application that I'm talking about. I don't remember installing it, and first time I see it in my launchpad, I drag it to trash and delete the application. A few days later I saw it in launchpad again.

The application is my app store purchase section, I tried to find a way to delete it from my purchases list. but could not find a way.

Any suggestion?

--- Edit ---

Could it be a kind of virus, or something? But I installed every app from app store