For many graduating from high school, trading memes over private channels might seem harmless. But Harvard University has reportedly revoked admissions offers for at least 10 previously accepted students over “messages that contained offensive messages and graphics” that were sent in a private group chat.

According to the Harvard Crimson, “at least ten” people who were initially part of the class of 2021 had their acceptance revoked after the admission office’s learned about the contents of a private Facebook chat.

The chat in question reportedly came out of a much larger private group chat that formed out of the official Class of 2021 Facebook page, which Harvard runs. It’s unclear exactly how many prospective students were involved, the Facebook allows users to message up to 150 people at once. That larger sub-group reportedly discussed relatively tame or positive memes. But a smaller group seemingly splintered off into a chat that included Holocaust jokes, racist memes, and jokes about child abuse. In one example, the Crimson reports that the hypothetical hanging of a Mexican child was referred to as “piñata time.”

“The Admissions Committee was disappointed to learn that several students in a private group chat for the Class of 2021 were sending messages that contained offensive messages and graphics,” read an email sent to some students in April and published by the Crimson.

“As we understand you were among the members contributing such material to this chat, we are asking that you submit a statement by tomorrow at noon to explain your contributions and actions for discussion with the Admissions Committee.” Later that same month, letters arrived for some indicating the offer was rescinded. It’s unclear who tipped Harvard off to the contents of the chat.

The hypothetical hanging of a Mexican child was referred to as “piñata time”

“Harvard College reserves the right to withdraw an offer of admission under certain conditions, which are clearly expressed to students upon their acceptance,” a 2015 statement from Rachael Dane, a Harvard faculty spokesperson, reads. “An offer of admission may be rescinded if a student engages in behavior that brings into question his or her honesty, maturity, or moral character.”

This isn’t the first time the university’s had to deal with an unruly incoming class on social media. Just last year, the college denounced offensive messages sent as part of an unofficial chat formed out of the official class of 2020 Facebook group.