The interview lasted for ~40 minutes. It was held on campus. The interviewer (an engineer from Michigan) and I talked briefly about different teams currently looking for internships and what appealed to me about each. Then we talked for several minutes about my past experience and relevant skills I learned. I was asked 3 "STAR" format interview questions from a packet of ~10 he had to choose from. My interviewer placed large emphasis on the thought process in each of my decisions, and took notes on his sheet throughout. At the end, I had a chance to ask more questions about different teams, as well as logistics, timing, and anything else. Hiring based only on a single behavioral interview without evidence of skills or abilities seems absurd, but hey, that's GM for you.