Beyoncé's choreographed flash mobs are the hottest ticket in music right now. First, B surprised a group of kids mastering her 'Move Your Body' moves in their school's auditorium and on Thursday, she snuck up on a group of shoppers at a Harlem, New York Target taking a dance lesson from her choreographer.

The crowd was dancing to her latest single, 'Countdown,' when Beyoncé emerged (to hysterical screams, naturally) and joined in, too.

[via Gawker]