I remember those vids. Even though spoony has completely gone off the rails (to be fair, he was always a little cowish, but now he's not even making content) and purely confined to insanely ranting on twitter nowadays, I still enjoy some of his stuff and listen to the Counter Monkey videos when I need myself some background noise. Some of the videos dealing with "that guy"s in particular are:
https://youtube.com/watch?v=Ut8TBd4Mr_w
If his rambling is too much for you, he talks about this pompous vegan guy who would game with him and his friends. Spoony, who was DMing, had the players try to find a genie to remove their curse. Once they found the genie, who could only grant one wish btw, Vegan Steve immediately asked for a deck of many things. You basically draw a random card, and you get what's on it, whether it be good or bad. There's a finite amount of good and bad things, and Steve chose to draw an amount of cards that was the exact same number of good cards. Unless he got it perfect, he would've run into at least one bad thing. The last card he drew killed him, while all the other cards were good cards.
https://youtube.com/watch?v=MeSVjfYaMGk
In this one, Spoony talks about Gary. Gary would arrive hours late to every D&D session, unless it was at his house. At one point, he said that he was late because he forgot to bring his pants.
https://youtube.com/watch?v=p-TWXdSQYxU
This one has him discussing the topic of "that guy" in general.
I remember there was also a video where he talked about guys who tried to sneak rocket launchers and other stupid shit in Call Of Cthulu. I don't remember which one it is tho.