Phone screening with an HR interviewer, then another call with engineering managers to test/quiz your engineering knowledge under pressure. There were to be additional rounds with more engineering managers and leadership. The HR recruiter was nice and great person to talk to, but did not send a second round interview confirmation. I was going to wait a few days before following up, but the engineering managers called and asked, in a very passive-aggressive tone, why I wasn't in the meeting. I told them I never received a confirmation or invite to said meeting. I agreed to do the interview on the spot, during which they asked questions about engineering concepts and previous experiences related to the position, but in the end they mocked me for being unprepared (to a meeting I was never invited to), for not meeting their expectations, and told me I was worthless to their company.