It’s 2 AM. Your phone buzzes, the on-call alert flashes, and suddenly you are staring at a production outage that makes no sense. Following the logs, you get a hint: when you rerun the same scenario in staging, everything behaves perfectly. None of the quality gates/QA pipelines catch it, chaos experiments didn’t reproduce it, and now a ghost is chased that only appears when the system is under real-world pressure.Distributed systems are notorious for these “phantom failures” — rare timing-dependent bugs that surface unpredictably and vanish just as quickly. They are the kind of dreaded incidents that keep engineers awake at night because they are unreproducible.