While Specter, a cyclops, only appears in one scene, her one line - "It's not easy being a parent... my girlfriend's daughter got me pulling my hair out, OK?" - has been enough to see the family film banned in Kuwait, Oman, Qatar and Saudi Arabia.
"Onward being banned in countries bc of that brief, barely even there, gay line, makes me hate the fact that I'm not straight," one Pixar fan tweeted in response to the news.
Another wrote: "Onward is banned from theaters at my country because of that one butch ogre cyclops hybrid with one line lmafo we stan a human rights first country."
Deadline reports that while Russia hasn't banned the movie, it has censored Waithe's scene, changing 'girlfriend' to 'partner' and not specifying her character's gender.
While the character is reportedly only in one scene, LGBTIQ+ organisation GLAAD last month celebrated the character as a sign of progress.
"This will be a breakthrough moment in representation when it premieres, and we hope to see more inclusion in animated films," the group tweeted.
Director Dan Scanlon said of the inclusive scene: “The scene, when we wrote it, was kind of fitting and it opens up the world a little bit, and that’s what we wanted.
“It’s a modern fantasy world and we want to represent the modern world.”
The movie follows the story of a group of elven brothers who attempt to bring their father back from the dead with a resurrection spell, only for everything to go awry.
Alongside Waithe, the film stars Julia Louis-Dreyfus, Octavia Spencer, Ali Wong, and Mel Rodriguez.