I don’t know how common it is anymore, but it definitely was a few years back. You knew a computer was infected with everything when you saw a stupid cartoon dinosaur or something as the mouse cursor as soon as the pc booted to windows… I think it was more about what was bundled in the download from scummy websites doing the damage though, not the actual cursor files. I still cringe though if I see a non-standard cursor in windows, like PTSD-esque flashbacks…
You can’t plagiarize mechanics because you cannot copyright mechanics… And you don’t want to live in a world where you can. Imagine if the first company to make a first person shooter game copyrighted it… Or if Nintendo owned the rights to all 2d side scrolling games… Gaming would have never grown to what it is today.
Hell, even board games would have been crippled by this kind of copyright.