speedwagoning 

Spreading gossip, rumors, or unconfirmed reports that rely on a chain of other unattributed sources, usually within a tightly-knit circle, and repeated often enough as to be taken as fact.

Basically, an anonymous circlejerk of damaging insinuations, that spreads like wildfire or a contagious disease, and is as catchy and easy to digest as an '80s earworm.

News reporter: Heard it from a friend who, heard it from a friend who, heard it from another you've been messing around.

Interview subject: That sounds like speedwagoning, and I'm not going to comment.

speedwagoning by Peppermint Marcie September 18, 2023

reo speedwagoning 

verb. to share a poorly sourced rumor as fact on social media. The information is unreliable, because, as the song "Take It on the Run" says, you "heard it from a friend who heard it from a friend who heard it from a friend" etc etc.

"Look at this GIF meme! Don't go to the mall today, there will be pee served instead of lemonade at the Orange Julius!"
"Wtf, this is just two people texting each other nonsense. Stop REO Speedwagoning".

reo speedwagoning by Peven glugh June 21, 2020