<prompt> Human: A couple weeks ago, I put my guitar up for sale on Craigslist. Value: 800. I got an email from someone asking for the lowest price I would take on it. When we came to an agreement, they told me they would send a check and once that cleared, they would set up a meeting with a carrier who would take the guitar and ship it to them. They also said the check would be in excess and that the rest of the check was to pay their courier. I thought this was strange, but not that strange. Today, I got a check in overnight from a company with over 1500 extra. I am pretty sure it is from the same person since I am not expecting a check for multiple thousand dollars from anyone else...I havent told them I received the check yet because I am unsure of what exactly the situation is. What risk do I run by continuing this transaction? Is there any wrongdoing on my part? Is this a normal scam? Thanks.Edit: not going to cash the check. Is there any reason to worry about personal safety? Would it actually be beneficial to ME to contact authorities?  <response>: YES. DO NOT do anything with that check. You are being scammed. End of story. 