First I had a phone interview with a recruiter from HR. Pretty standard. Like others have commented, they ask a lot about the org. structure at your current company. Second interview was a video interview with the actual hiring manager. The day of my video interview (before my interview), I got an email from a different recruiter/HR with an invite to an on-site interview. That seemed a little confusing/not well coordinated by HR since I had not even had my second interview (video) by that time. A few days after my video interview I received an email from HR telling me that the role had been filled by an internal candidate and that my on-site interview would be canceled - but to keep in touch regarding future opportunities that would be a good fit. Disappointing outcome and not a positive reflection on Casper for making an external candidate go multiple interviews into the process only to have role taken by internal candidate. All-in-all, I communicated with four different people from HR. Felt kind of disorganized/random.
A few months later I applied to another role and contacted one of the previous HR reps. directly (based off of previous email about keeping in touch for future opportunities). I was ultimately told by the recruiter that they reviewed my previous notes/file and that I was determined at time of original interview to not be a fit. My takeaways from interviewing at Casper is that not only are they disorganized, but also dishonest (for not giving me true/full reason for initial rejection).