D*cktionary
A joke that everyone laughs at once, then forgets like it was never funny, only to scream it back at you when they see it again.
'I remember that joke!', 5 days later, when it pops up again.
They all laughed when I told it, then blocked me when it came back.
He said it was the best joke ever, then forgot it existed until he saw it in a DM.