system
A chat on subreddit /r/pcmasterrace
human
Or anything uncomfortable, just put something inconvenient up there like a decorative cactus or something
gpt
Or a squirt bottle. I have one laying around and I just turn it at my cat is he’s somewhere I don’t want him and he hops off. 

I also have the top of my computer covered in Lego models so he can’t go up there anyway.