Okay, so this probably sounds like a massive red flag. It's for a medicine side effect in my game. It's gonna do stuff like show fake debug messages, put the client in a "process not responding" state, stuff like that.

My current charge is the latter of the two: Making a specific player's client temporarily stop responding. I am aware you can send them large audio files, but this does not achieve the goal of lagging a SINGLE player out, instead it causes everyone to chug as the file is cached. I only want the affected player to chug.
You're much better off simulating the issue as movement delays or something of that nature. When the client "freezes" there's a good chance Windows will still that and try to close it.
Dude, you're better off just using filter effects to screw with the player's view.