Dang it, did i miss it? What? It exploded? WTF
No, one of the nine engines on the first-stage booster exploded in-flight. Falcon 9 was designed to take this hit whereas any other booster that suffered an engine explosion likely would have scattered itself across the sky.
Listening to the video it happened right after Max-Q, the point of maximum aerodynamic pressure on the booster. Big fireball out of one engine and the stack keeps moving like nothing happened.
Build a man a fire and he's warm for the night. Set a man on fire and he's warm for the rest of his life.