The sparkling lights in the audience at Eleague’s CS:GO major in Boston come courtesy of light-up bracelets given to every attendee. The bracelets flash red at the same speed as the in-game bomb countdown, they light up white for explosions, and flicker either yellow or blue for a terrorist or counter-terrorist victory, respectively.

Unlike the Blizzard Arena’s halo for Overwatch League, these bracelets light up simultaneously with the game’s events, so they probably aren’t controlled by a human hand... probably.