The student union at Brock University says there are some Halloween costumes that just aren't OK.
The union has issued a list of costumes that won't be allowed at its annual party.
They include any form of headdress, costumes that mock suicide or rape, those depicting transgender activist Caitlyn Jenner, or outfits featuring a culture's traditional attire.
Some groups, however, have complained the list is equivalent to censorship.
It was two years ago, the school made headlines after a group of students, dressed in blackface as the Jamaican bobsled team from the movie Cool Runnings, won a Halloween costume contest at the university's pub.