On Brazil's free kick toward the end of the first half, World Cup viewers got their first look at one of this tournament's new wrinkles: A can of vanishing spray used by referees to mark off the distance defenders must stand from the ball.

After counting off the 10 yards from the ball, the referee lays down a line of the water-based foam—all the better to keep those 10 yards from turning into seven or eight as defenders press forward. The foam will completely vanish from the pitch in about a minute.

"It's a vital tool for ensuring that the rule is observed," said Howard Webb, who believes the strict enforcement of the 10-yard zone could lead to more goals.

Sam Borden at the New York Times gave us the heads-up on the foam yesterday, which has existed in one form or another for more than 20 years, but didn't see regular usage until a modern formulation began being used in domestic leagues, including America's and Brazil's, a few years ago. After test runs at last year's Under-20 World Cup and this winter's Club World Cup, it'll be a standard part of the referee's arsenal at this tournament.

There are no drawbacks. And all the opportunity in the world for a little physical comedy:

What's Up With That Spray The Referee Used On Brazil's Free Kick?