Went through the Mars behavioral round for a tech manager role a few months back. Wanted to write this up because their value system is legitimately distinctive compared to the generic "leadership principles" stuff you see at other companies.
Mars has their Five Principles: Quality, Responsibility, Mutuality, Efficiency, and Freedom. These aren't decorative. They come up in the behavioral interview in a real way. The interviewers asked questions that clearly mapped to specific principles even if they didn't name them out loud.
Questions I remember "Tell me about a time you held to a quality standard when there was pressure to ship faster." (Quality) "Describe a situation where you had to think about the impact of your work on people outside your immediate team or company." (Mutuality and Responsibility) "Give me an example of when you pushed back on a decision you thought was inefficient." (Efficiency) "How do you make decisions when you don't have explicit direction from leadership?" (Freedom)
The Freedom principle is interesting because it means they don't want people who wait to be told what to do. They want autonomous decision-making within guardrails. That came up twice.
Format Pure STAR. One interviewer, 45 minutes, about 4-5 questions. No case study in this round (manager-level). They listen carefully to the Result portion of your stories. Weak results get a follow-up: "what would you have done differently?"
What I noticed they weren't impressed by Stories where success was "we launched on time." They pushed for actual impact. What did the customer experience? What metric moved? One interviewer said something like "outcomes, not outputs" when I gave a shallow result.
Overall Prepare actual impact stories. Know the Five Principles. Don't fake alignment with them because they'll probe it. But if you genuinely care about things like sustainability and long-term thinking, that comes through and they respond to it.