Musk said on Twitter that his tunnelling project, The Boring Company, would soon begin re-selling rocks they excavated as “LEGO-like” bricks, and that the first set would be ancient-Egypt themed.

First kit set will be ancient Egypt — pyramids, Sphinx, temple of Horus, etc

— Elon Musk (@elonmusk) March 26, 2018

The characteristically bizarre Tweet thread from Musk incited debate among his followers. Was this for real? Did he actually mean he was going to send out pre-fab sets to build life-size Egyptian pyramids as he seemed to imply in his first tweet?

Wait a minute. LIFE SIZED?? Sphinx and pyramids??

— Linda C., M.A. (@lcathcart4596) March 26, 2018

After the flamethrowers, I treat all his tweets as if they're real 😂

— Kaleb ✨ (@Kubbaj95) March 26, 2018

Are you sure you aren't a bond villain?

— Benjamin Jaeger (@tiredhunter) March 26, 2018

Musk later implied that the bricks were actually intended for construction rather than novelty:

Yeah, the boring bricks are interlocking with a precise surface finish, so two people could build the outer walls of a small house in a day or so

— Elon Musk (@elonmusk) March 26, 2018

There is precedent for such a stunt. Earlier this year, Musk and The Boring Company sold 20,000 flamethrowers (or, more precisely, not-a-flamethrowers). The $500 fire guns and their complementary product, the “overpriced Boring Company fire extinguisher,” sold out within a week.

The Boring Company’s website doesn’t make reference to the bricks Musk seems to be describing, but it does acknowledge the waste associated with building tunnels, and says the company is “investigating technologies that will recycle the earth into useful bricks to be used to build structures.” Where the pyramids fit in to that plan remains unclear.