People who don't get animals in their computers
So, the title is a slight lie. This is my house mates computer, my cat caught a baby brush tail possum, it went running into his computer. He asks me what to do about it, not in an IT help, just a 'wtf is that thing and what can I do' help. I told him, gave him numbers for Fauna Rescue. They tell him to take it to the closest 24hr vet that can handle wildlife (which was only a few km away). He takes it there and drops it off with his details. Hopefully it is being rehabilitated, we haven't heard anything since.
For the record, the comp was off, and it was never at risk or a risk to the computer, it was at risk of shock and infection from my cat so we got it to the vet asap.
People who understand proper cooling
This right here is the real gore.
So, did you friend use the computer as a box to carry it to the vet? :D Why was his computer open anyway? (I mean, I guess it was, since this cute thing entered it?)
People who are done testing and installing parts?
Baby brushtail possum
Partner you're in a tech support subreddit did you really think anyone was going to realize you're kidding?
Who doesn't keep their computer open
Different species to the ratty thing clawing around inside American dumpsters.
Go with the flow.
when does that happen?
yeah... it interrupts the normal flow of hot air and replaces it with ambient air. :P Find me one source where people actually measured higher temps with the case open.
What even is that?
Not true. I once accidentally closed one of my cats inside my PC when they were a kitten, and I keep my PC closed unless I need to open it for some reason.