chain letter
A message that instructs the recipient to send copies to multiple people, often with promises of luck or threats of bad luck. In modern contexts, it can refer to email or social media chain messages as well.
When you receive a chain letter, it's best to ignore it.
Chain letters used to be popular as physical mail, but now they spread on social media.
Variant with interpunct; less common but still seen.
Loanword from English 'chain letter'.