Elon Musk is like that favorite high school teacher: Half taskmaster, half curiously fun. You never know which version you’ll get on a given day.

The witty Tesla founder and potential Twitter owner just announced an ultimatum to his Tesla staff Tuesday: Return to the office to work or you’ve quit. According to emails, Musk requires car-company executives to work a minimum of 40 hours per week in office and exceptions would be made only for exceptional contributors on a case-by-case basis. READ MORE