Call with recruiter, then call with director + lead engineer. Had short discussions with team members as well. Final call with senior VP. After all that, had to write three past achievements with clear quantitative results to get approval from Elon Musk
I had a round of portfolio review with a panel, then some general behavioral questions. It was great and the interviewers are really really nice. I enjoyed the interview very much.
The internship interview is challenging but smooth process. Depends heavily on team and specific job role how technical it may be. 1-2 rounds with mentor and manager after recruiter screening can be expected.