What Are They Spraying All Over the World Cup Fields?

If you're a red-blooded American watching the World Cup, you probably have had two questions pop into your head over the past few days: Can the U.S. make it out of the group stage (we totally can), and what the heck are the refs spraying on the field?

Referee Yuichi Nishimura sprays a temporary line on the field marking 10 yards as players from Brazil and Croatia form a wall during the 2014 FIFA World Cup Brazil Group A match between Brazil and Croatia at Arena de Sao Paulo on June 12, 2014 in Sao Paulo, Brazil. (Elsa/Getty Images)

It's not shaving cream or spray paint, but a specially-designed temporary foam, and it's a brand-new tool in the World Cup referees' toolbelt.

A 'Brazuca' match ball sits near a temporary line sprayed by the referee for a free kick during the 2014 FIFA World Cup Brazil Group E match between France and Honduras at Estadio Beira-Rio on June 15, 2014 in Porto Alegre, Brazil. (Paul Gilham/Getty Images)

As Gizmodo explains, the inventor of the spray is one Pablo C. Silva, an Argentine journalist and amateur soccer player who got tired of watching players cheat on free kicks.

When there's a foul committed outside the goal box in a soccer game, the offended team gets a free kick and the offending team must stand at least 10 yards (9.15 meters) away from the player taking the kick.

But in much the same way that players taking a free throw will edge down the line, or a player taking a kick will nudge the ball upfield, players defending against a free kick have a tendency to scoot closer to the ball, especially if the refs aren't paying close attention.

Silva's spray is designed to stop such cheating in its tracks — and to do so without leaving permanent stripes all over the field.

Made of a unique combination of water, butane, and surfactant served up in an aerosol can, Silva's formula disappears a few moments after use.

The spray appears to be doing its intended job, though whether the use of vanishing spray and goal-sensing cameras actually makes the sport better — or if it's just another step towards robot soccer — remains up for debate.

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