Illinois officials are warning that a viral game promoted on social media and featuring water guns could trigger actual violence from fearful targets — or police.

The game, called "Senior Assassins" involves teams of high school students donning ski masks and targeting each other with water guns that look like actual firearms in a competitive "shoot out."

Police in Gurnee, Illinois, said an armed patron feared an actual assault earlier this week when masked teens from a neighboring community entered a restaurant with toy guns drawn.

The adult, who was legally allowed to carry a concealed weapon, "mistook the situation for a genuine threat and the situation could have escalated quickly," the local police department said in a statement on Facebook.

"The Gurnee Police Department would like to emphasize that the depiction of firearms, whether real or imitation, in any public setting, is a matter of concern and may instill fear among the public," the statement noted.

"We urge community members to reconsider their participation in such activities and recognize the seriousness of their actions," it added.

Police offered no other details about the restaurant faceoff.