"This is a relay call." What the [censored]'s a relay call?

[mmbt0ne]

I just got a phone call, where apparently some douchebag is typing on his computer, and this putz talks to me and tells me what he types. Then, I reply, and he types to douchebag whatever I say. Now, I've never heard of this before, so I'm intrigued enough to go through the whole instructions, and see what's going on.

Anyway, the conversation doesn't last long, because the response to my "Who are you?" question was "Your father-in-law," which is obviously a lie. Somehow he knew my name though, which is kind of, ok, really, scary/weird.

Is this some sort of new phishing scam? I'm disappointed in myself for not keeping this conversation going longer, and seeing what I could find out, but obviously I wasn't thinking. Either way, the fact that someone has both my name and cell phone number, and feels the need to call me through some relay line, and tell me they're my non-existent father-in-law is kind of freaking me out.