After a Tesla owner refers five new owners (who get $1,000 of their car, plus unlimited Supercharging), they unlock the first Secret Level, which lets them provide five more referrals. If they refer those five new buyers, they can get 10 percent off the price of a next-generation Tesla Roadster. That also unlocks Secret Level 2. At that point, the owner receives another message:
"You've unlocked the second secret level. Share your referral code to give 5 more of your friends free unlimited Supercharging and $1,000 off a new Model S or Model X. Once all 5 take delivery, we'll give you the opportunity to drive an electric tunnel boring machine with The Boring Company in Hawthorne, CA."
The Boring Company, which is another venture by Elon Musk, recently addressed Hawthorne City Council to propose building a two-mile long tunnel for SpaceX research and development. Musk also say he has received verbal approval to build an underground hyperloop transportation system connecting New York City, Philadelphia, Baltimore, and Washington, D.C., and has discussed digging tunnels under Los Angeles as well.
The Secret Level messages also note that each referral provides another two percent off the price of the next-gen Roadster. With enough referrals, Tesla says, the Roadster will be free.