Photo by Mike Mozart/Flickr.

America’s largest arms dealer, Walmart, took heat this week after a disturbing display was discovered in one of its stores. A Twitter user posted the photo of a rack of rifles in a glass case with a sign atop that read, “Own the school year like a hero,” and it quickly went viral. Although it’s unclear whether the display was created by an employee or a shopper with a despicable sense of humor, the retail giant removed the display after being notified and made a public apology.

The signage atop the display had nothing to do with guns; it’s part of a superhero-themed back-to-school campaign. The juxtaposition of firearms and a back-to-school message is disturbing in a nation plagued by school shootings. This point wasn’t lost on Leeanna May, the person said to have taken the first photo of the display in Evansville, Indiana. “We have already lost so many innocent lives to guns,” May told The Washington Post.

Charles Crowson, a spokesman for Walmart, issued a statement saying, “What’s seen in this photograph would never be acceptable in our stores. We regret this situation and are looking into how it could have happened.”

Walmart’s social media team was busy on Twitter on Wednesday, apologizing for the display.