After the tweet drummed up the requisite chaos, reporters logically dialed the number, which went voicemail. But because this is Elon Musk -- sci-fi aficionado and ruler of the universe -- the voicemail message, (or perhaps ringtone, as others have pointed out) was a recording from the classic Playstation game God of War, which in part reads:
"By the Gods you've done it. Somehow you've found your way here to me. I offer you my congratulations and my respect."
Musk hasn't answered the line, and some are saying the whole thing could just be a prank, as it's often the CEO's wont to be playfully mischievous. But then again, when you're said to be the real-life incarnation of Iron Man, you probably get a lot of phone calls.