Childlore is folklore passed directly between children, without the input of adults.
https://en.wikipedia.org/wiki/Childlore
Stuff I can think of off the top of my head are paper fortune tellers, summoning Bloody Mary/the candyman, the cool S, parody songs like “Jingle bells Batman Smells” and “Joy to the world, the teacher’s dead” etc.
This stuff has intrigued me since, well since I was a kid. I always wondered where they came from. I never saw adults doing that stuff, so I figured another kid had to have come up with it.
Okay, so back in the 1990s Charter Medical Corporation ran a suicide prevention hotline with the number 1-800-CHARTER. They ran a massive TV ad campaign with the tagline “If you don’t get help at Charter, please, get help somewhere.” These commercials ran on daytime TV so they were a little…oblique. Euphemistic. So that children wouldn’t understand them. So we didn’t.
Around that time, it was popular slang among teh youthz to say “you need help” as a way of calling someone stupid. You can hear one of Roger’s daughters say it in the first Lethal Weapon movie in response to his attempt at rapping.
And of course, people who “need help” should call Charter. So in the 1990’s there was a fad of us school kids calling each other stupid by saying “You need to call Charter.” And I wonder how local that was, I know at least two elementary schools in my county did that. American Millennials, do you remember this?