Final answer:
The message in question is an example of a chain letter, which is a type of message that encourages recipients to forward copies to others, often with promises of rewards or threats of negative consequences.
Step-by-step explanation:
The message “Dear Alex, mail this to 10 of your pals & make $1,000 or your mustache will grow back” is found in chain letters. Chain letters are messages that attempt to convince the recipient to make multiple copies of the letter and then, to pass them on to a certain number of recipients. The message typically contains various promises of good luck or money in return for completing the task or warnings of bad luck or negative consequences if the task is not completed. The format of these letters varies, but they were originally sent by postal mail and have evolved into electronic formats such as emails.