A Burnsville High School student came under fire over the weekend for an offensive poster that he used to ask a black student to the homecoming dance.

The sign reads: "You may be picking cotton but I'm picking you. Homecoming?"

Clusters of what appear to be cotton balls are glued to the cardboard sign. A photo depicting the smiling boy, who is white, with his arm slung over the girl's shoulder while she holds the message, sent ripples of outrage across social media, beginning with Snapchat and eventually including Instagram and Facebook. A caption on the photo says, "She actually said yes," with a fearful face emoji.

School officials say they later learned it was meant to be a gag between friends, who were surprised about the negative reaction.

In an e-mail sent to parents on Saturday, Principal Dave Helke characterized the circulating photo as "deeply offensive" without describing it.

"I want to make it clear that the posting does not align with the values of Burnsville High School and Burnsville-Eagan-Savage School District 191," Helke wrote. "We value all students, expect all students to take responsibility for exhibiting that with their peers, and work in many ways to build up each other as a community of caring individuals. "

The young man involved in the incident, a junior, removed the post, replacing it with a public apology for the "racist remark" to his social media accounts Saturday morning.

"I made the poster as a joke between my close friend and I and many took it the wrong way and were offended," he wrote in a message posted to Twitter. "I'm sincerely sorry, no intentions were ever to offended [sic] her or anyone of color it was made as a joke."

It remains unclear whether the student will receive any sort of disciplinary action.

"The principal sees this as a teachable moment," said Ruth Dunn, spokeswoman for the district, who added that the incident did not happen at school.

Homecoming week begins Monday at Burnsville High School. The annual dance will follow Saturday in the school gym.