Invasion of Privacy

Just delete or blacklist him. Of course that doesn't work well if they use multiple e-mails to send their spam but it might make you feel better. Probably a good assumption nowadays that your e-mail address is in the hands of at least some people you don't want to have it. If you get mass spamming from a pattern that might be recognizable, maybe your internet provider can help. As long as they can't actually take your identity they're more of a pain in the a@@ than a threat (imo).