Thousands of United States soccer fans grabbed their heads in shock as Portuguese player Silvestre Varela headed the ball into the net in the final 30 seconds of play Sunday night, ending the World Cup match in a soul-crushing tie.

The simultaneous head-grabbing in the stands is called a "pacifier" gesture because it's meant to self-soothe in times of disaster, according to Chris Ulrich, a senior instructor at the Body Language Institute in Washington D.C. People feel safer and smaller from threats with their hands on their heads or over their mouths, he said.

OK, the outcome of a soccer match isn't exactly a threat. But we were winning right before the upset!

Check out other universal gestures and find out why surprise looks the same in every country.

Find out how the United States can still advance from the "Group of Death."

See all the best moments from the World Cup.

U. S. spectators at the World Cup grab their heads in shock when Portugal scored a goal in the last minute of stoppage time, evening the score. (Credit: ABC News)

Fans in Grant Park react during a Group G World Cup soccer match between Portugal and the U.S. on June 22, 2014 in Chicago. (Credit: Scott Olson/Getty Images)

ABC News' Gillian Mohney contributed to this report.