Atlas, a statistical anomaly detection system developed for Elasticsearch, leverages pipeline aggregations to distill large datasets into key metrics, focusing on the 90th percentile of "surprise" values, or deviations from the moving average, to identify anomalies over time. The system employs TimeLion for post-processing, graphing these variations, and setting alerts when deviations exceed three standard deviations above the moving average. This setup enables efficient anomaly monitoring without examining vast quantities of data directly, by highlighting significant variance changes that suggest disruptions. Despite the limitations of current pipeline aggregations, such as their inability to select the "last" surprise value, Atlas remains effective, even with skewed data distributions, by relying on its ability to track and respond to significant shifts in data variance. Future enhancements may include integrating alerting systems like Watcher to automate notifications for detected anomalies.