KEY POINTS
  • Elon Musk "may be proof that time travel exists," says the ex-Twitter CEO, in praising the former's ability to multitask.
  • Costolo's comments came after Musk tweeted about getting "verbal" government approval to begin building an underground hyperloop from New York City to Washington, D.C.

Mention Elon Musk and let the superlatives fly.

But former Twitter CEO Dick Costolo just brought praising Musk — the billionaire entrepreneur behind electric cars and solar power solutions, space travel, and ambitions of digging transportation tunnels under cities — to a whole new level.