It’s not often an interview begins with the words, “Tell me about the buttholes.” Ask any Cats fan, however, and they’ll regale you with tales of the $100 million-losing Hollywood disasterpiece’s elusive “Butthole Cut.”

The root of Cats’ muddied visual effects, it turns out, might have been more than just a time-crunched production. Director Tom Hooper, a source alleges, had no idea what an animated production entails—and he made life hell for the visual effects artists struggling until the bitter end to figure out what he wanted.

Cats was already halfway complete when the buttholes first showed themselves, a source who worked on the film’s visual effects recalled in a recent interview: “When we were looking at the playbacks, we were like, ‘What the hell? You guys see that?!’”

“We paused it,” the source said. “We went to call our supervisor, and we’re like, ‘There’s a fucking asshole in there! There’s buttholes!’ It wasn’t prominent but you saw it… And you [were] just like, ‘What the hell is that?... There’s a fucking butthole in there.’ It wasn’t in your face—but at the same time, too, if you’re looking, you’ll see it.”

The rogue anuses, we should probably note, were not part of any concerted artistic vision. As the source put it, “There was nobody that said, ‘We want buttholes.’ It was one of those things that just happened and slipped through.” And indeed, one poor, unfortunate soul was subsequently hired to squeegee them out.

Cats’ visual effects have also become a popular punchline. Twitter users memed the film’s much-touted “digital fur technology” from the jump—and once the film premiered, people laughed at flubs like characters’ feet not touching the ground and Judi Dench’s exposed hands. Stars James Corden and Rebel Wilson even ridiculed their own movie at this year’s Oscars: “As cast members of the motion picture Cats,” they said while presenting, “nobody more than us understands the importance of good visual effects.”

Twitter user Yves McCrae, who says he worked on the film, called the joke out, writing, “Hey guys I haven’t watched all of the Oscars but I assume these two were really classy and thanked me for working 80 hour weeks right up until I was laid off and the studio closed, right?” And from the sounds of it, one can easily understand why Corden and Wilson’s joke drew ire. The visual effects industry is already a difficult one to work in—and Cats, it seems, was a particularly thorny production.

The visual effects source I spoke with described the situation as “almost slavery,” and recalled working 90-hour weeks for months. Some colleagues, they recalled, stayed in the office for two or three days at a time, sleeping under their desks. But worst of all, the source said, was the treatment visual effects staff received from Tom Hooper. The director, the source alleged, has no idea how animation works—but that did not stop him from sending crew members individual emails denigrating their work. (Hooper and distributor Universal Pictures did not respond to multiple requests for comment.)

Before visual effects artists fully render sequences for animated films, they normally show directors playblasts—preview renderings that feature characters without color or texture. That allows the director to evaluate the motion before hours of work are done to flesh out things like color, texture, and lighting. Hooper, however, did not seem to grasp that process. Any time the visual effects team wanted to show the director any animatics, the source said, they had to fully render it. Otherwise, he’d say things like, “What’s this garbage?” and “I don’t understand— where’s the fur?”

Some aspects of the production, the source alleges, became simply absurd—like when Hooper would demand to see videos of actual cats performing the same actions the cats would do in the film. “And as you know,” the source said, “cats don‘t dance.”

Multiple times during our interview, the source described Hooper as “horrible.” Other adjectives included “disrespectful,” “demeaning,” and “condescending.” “When you go into a conference room, you’re not allowed to speak,” they said. “And he talks to you like you’re garbage.”

It took the team six months to produce the film’s two-minute trailer, the source said. After that, roughly four months remained to complete the entire film. Visual effects supervisors were the only members of the team who met with Hooper—and by the end of production, Cats had  burned through multiple.

“It was pure, almost slavery for us, how much work we put into it with no time, and everything was difficult,” the source said. “We were so rushed on the project that we’d have no time for anything. So when people say, ‘Oh, the effects were not good,’ or ‘The animation’s not good,’ or anything, that’s not our fault. We have no time. Six months to do a two-minute trailer and four months to do a film of an hour and a half. My math is pretty good... You could figure that doesn’t make any sense.”