This would be in a similar style to the new "Media in Deltarune" page. Not only would this be a better place to list the info on the dead pixel gag (currently it's all mentioned in a disambiguation page), it would also be able to list info on the "realistic explosion" gag; "Explosion" is currently one of the most common failed searches. It should also list info on the Chapter 2 banana gag (another very common failed search), and any other running gags that I'm forgetting about.
the problem with this is that it's a very vague category. what's the limits of what could be included? a joke mentioned twice? thrice? what's the deciding factor on what's a joke and what's not? obviously "quiet people piss" is recurring and not a gag, but other future things might be more vague
...are my preliminary thoughts. if nobody else finds that very relevant go ahead.
also, have you considered making a user sandbox page first? have it be titled "PapyrusPikmin1997/Running Gags" rather than "Running Gags" to get the concept solidified before making it an established page
okay i don't think a lot of those sections have enough content to warrant a section. do we have any evidence to saying that water coolers saying "boobie" was intentional? the string is randomly generated, it could be an accident. and "your taking too long" should just be covered at jackenstein's page it doesn't need to be here as well
The "boobie" for the Watercooler fight is almost certainly intentional as the double oo possibility only results in it and "booble".
As for YOUR TAKING TOO LONG, its section on the gag page is good to keep as it keeps all the phrase's appearances in one section. On the Jackenstein page, the user would have to read through all the dialogue. (Having a section on that page for the phrase would be unfitting)
Smorgasbord: I don’t see anything noteworthy about this concept which isn’t even in all four chapters. If this is a running gag, where’s the “gag”? Mixed enemy encounters are a common thing in games, I’m pretty sure.
Papyrus: there’s no reason to document him as a running gag if he’s already documented as a character. Nobody is going to search for Papyrus information on the Running Gags page, and it’s just duplicating content from his character page.
Watercoolers: not particularly “running”, considering that it’s just a character that reappears multiple times. I wouldn’t call it a running gag just like I wouldn’t call the Royal Coat Rack a running gag.
YOUR TAKING TOO LONG: this isn’t “running” by any metric. It’s just Jackenstein.
Five, to my knowledge? And only twice is it mandatory?
It’s one of the items Tenna announces as a prize when we first meet him, also one of the quiz questions is about the plush, and the plush appears again if you don’t push Ralsei in the first block puzzle that requires you to. It also appears if you throw Ralsei into the water in the room where you find the croissant.
Ralsei also turns into it if you R-Action “PopularBoy” during the final Tenna fight