# Blazar variability - expect the unexpected

## TL;DR

This paper reviews the unpredictable variability of blazars, highlighting unexpected events in four well-monitored sources despite advances in data and theory, emphasizing the complexity of their behavior.

## Contribution

It provides an overview of unexpected blazar behaviors observed in four key sources, illustrating the challenges in predicting their variability.

## Key findings

- All four sources exhibited highly unexpected events.
- Blazars remain unpredictable despite extensive monitoring.
- The study underscores the complexity of blazar variability.

## Abstract

Despite significant progress in both data taking and the development of theory, blazars keep offering surprises. While many frequency bands are now covered by long-term monitoring efforts on at least a few selected sources, blazars remain unpredictable and the same source may exhibit vastly different behaviors. Here, an overview is given about four selected sources, namely 3C 279, PKS 2155-304, PKS 1510-089 and CTA 102. All of them exhibited, indeed, highly unexpected events.