Since then, the Internet has lit up with speculation of just what we could be in for when Musk takes the stage next week. The hype has only gotten bigger now that journalists have received their invitations to the event — TechCrunch writes that it will be held at Hawthorne Airport near Los Angeles.

And so we reach the million-dollar question: what are we in for? Unlike with some supposedly secret corporate product announcements — I’m looking at you, Apple (AAPL) — no one is quite sure what to expect.

It could be really big. Tesla’s (TSLA) first self-driving car, maybe? Engadget notes that in an interview recently Musk said he thinks there will be a self-driving Tesla next year, although he did not specify whether or not that’s either the D, or the other product he’s planning on unveiling next week.

TechCrunch points out that this rumor has a bit of evidence for it in the form of Tesla’s recent software updates. Seth Weintraub has pointed out on electrek that the latest software has included land departure and speed assist features, both hallmarks of the automation evolution that’s coming to vehicles. Add on the fact that General Motors (GM) recently announced plans to get electric cars on the road in the short order, and it would make sense that Musk wants to get out ahead of the old-school Detroit giant, if only to maintain his cred as an innovator.

Matt Burns of TechCrunch points out another option for the reveal though: a high-powered, ultra-high performance supercar version of the existing Model S. This could mean two electric motors, Burns writes, and the battery technology needed to make the thing run. It could mean making the car even more aerodynamic. It could, Burns notes, be the “insane” kind of car that filthy rich enthusiasts would love to take out for a drive.

TheStreet.com notes two other options: senior analyst at Kelley Blue Book’s KBB.com told the site he thinks the product will be a truck, or a van, which would obviously add a whole new demographic to the Tesla family of consumers. Mark Takahashi, editor at Edmunds.com, told site he thinks the announcement will go in another direction and be the introduction of an entry-level coupe. If priced right, that could help bring Tesla move towards the mass market, and make the electric car less of a niche item.

There is a less exciting possibility as well: that the D will just be another version of the Model S. The Verge notes that someone in a Tesla enthusiasts forum posted a picture of a Tesla with the model tag “Model S P85D.” Tesla already makes a Model S P85. Is this just an upgrade?

It would seem odd for Musk to make such a big deal on social media if the new product is just a tweak to an existing car. Of course, he also said there would be “something else.” Some have speculated this could be something completely different, such as an electric motorcycle.

Whatever it is, you can rest assured that after Musk leaves the stage next Thursday, the same people who’ve been speculating will start kvetching over what he did right and what he did wrong.