Tesla Motors (NASDAQ:TSLA) CEO Elon Musk is stirring the pot again. Teasing an upcoming announcement and making a bold prediction about self-driving cars sent shares soaring nearly 5% today. Here's what you need to know.

What's the wild card?
In Tesla's most recent earnings call, Musk dropped a bombshell in the form of a surprising hint.

"In the past, we've shown all of our cards. So, people have kind of gotten used to us showing all of our cards," Musk explained. But apparently, this isn't how Tesla operates anymore. "We're not currently showing all our cards."

Again, later in the call, Musk explained that Tesla's capital expenditure and research and development expenses are actually "better than they appear because there are things you don't know about."

What sort of things could Tesla be working on? We're likely to find out on Oct. 9.

Tesla CEO Elon Musk tweeted this image Wednesday evening, saying it was "about time to unveil the D and something else." The awkward wording, he said in a tweet a few minutes later, was not intended. Image source: Tesla Motors.

The D must be one of the cards Tesla said it wasn't showing during the company's Q2 call. But Tesla says the D won't be the only surprise on October 9. The company will also announce "something else."

Given that the vehicle teased in the image looks exactly like a Model S, we're left pretty clueless as to what exactly Tesla could be planning to show off on Oct. 9. What we do know is that Musk told The Wall Street Journal last month that the company would soon be making a "significant" announcement about a product that was not a new vehicle. This has sparked speculation that the company could be announcing all-wheel-drive upgrades to the Model S or possibly new self-driving features.

Self-driving cars are coming sooner than you think
As if a teaser of a mysterious announcement wasn't enough hype, Musk told CNNMoney today that a Tesla vehicle will be 90% self-driving by next year.

"Autonomous cars will definitely be a reality," Elon Musk told CNN's Rachel Crane in an interview. Musk, who prefers to use the word "autopilot" over "self-driving," went on to say that "A Tesla car next year will probably be 90% capable of autopilot -- like, so, 90% of your miles could be on auto." And Musk said highway travel would "for sure" be autonomous by next year.

How will Tesla implement the technology?

"With a combination of various sensors. You combine cameras with image recognition with radar and long-range ultrasonics -- that'll do it," Musk said.

True to the Silicon Valley, the Model S features a 17-inch touchscreen. Image source: Tesla Motors.

Musk insisted that Tesla will be a leader in self-driving cars: "I mean, Tesla's a Silicon Valley company. If we're not the leader, then shame on us."

New announcements and a shot at leading the way in self-driving cars are definitely items that improve the outlook for Tesla's business potential. Yes, a $30 billion market capitalization has priced in both astronomical growth potential and surprises. But this California-based company continues to prove it is a disruptor. Tesla management's big ambitions, excellent execution, and huge potential give the underlying business the characteristics of the sort of company investors want in their portfolio. While it's tough to call the stock a buy at these levels, shareholders definitely shouldn't sell.