Colleges around the country are gearing up for Halloween by warning students about the consequences of wearing “offensive” costumes.

Fox News reports universities around the country are preparing to comfort distraught students scarred by insensitive costumes worn by their peers on Halloween. In 2015, a video of students berating Yale Professor Nicholas Christakis over his liberal stance on offensive costumes went viral.

Administrators at Tufts University have set up a reporting system for students who want to report costumes that they have deemed offensive. “We encourage all students that feel like they have encountered someone who is wearing an inappropriate and offensive costume to please file a report by filling out the following link,” a note from the university read.

“Greek Brothers and Sisters have worn costumes that appropriate cultures and reproduce stereotypes on race, gender, sexuality, immigrant or socioeconomic status,” the letter sets out. “Outfits relating to tragedy, controversy, or acts of violence are also inappropriate. We need to set a precedent that people’s customs cannot and will not be our costumes.”

The University of Texas gave students a 29-point checklist on offensive costumes. The checklist reminded students that even seemingly innocent costumes can be deemed harmful.

Princeton University held a dialogue with students about the impact of culturally-offensive Halloween costumes, while a flier distributed at the University of St. Thomas also warned students that cultural appropriation in costumes is offensive. “Unacceptable costumes” listed on the flier included “Native American headdresses, dressing up as a ‘Mexican’ by wearing a sombrero, dressing as a ‘geisha,’ any form of blackface.”

“Cultural appropriation is defined as ‘the act of taking intellectual and cultural expressions from a culture that is not your own, without showing that you understand or respect the culture,’” the flier read.

One activist on Twitter took issue with a Pink Floyd-inspired costume from retailer Party City, which he called “directly racist” for its similarities to Donald Trump’s proposed border wall.

Last year, the University of Florida offered round-the-clock counseling services for students traumatized by Halloween costumes.

“Some Halloween costumes reinforce stereotypes of particular races, genders, cultures, or religions,” the administration wrote. “Regardless of intent, these costumes can perpetuate negative stereotypes, causing harm and offense to groups of people.”