“A Goofy Movie” was rescued by a tiny black speck.

For those of us who grew up in the 1990s or early 2000s, A Goofy Movie was everywhere. Substitute teachers showed it during the last lazy days before summer vacation. Disney Channel played it during prime cartoon-watching hours. And friends loaded up the VHS tape during sleepovers. The 1995 blockbuster disappointment deserves the cult classic status it eventually attained: It has great music, heartfelt scenes, and a poignant message about father-son relationships, all wrapped up in antics, as Goofy bonds with his son Max.

Just in time for the movie’s 30th anniversary, Disney Plus’ new documentary Not Just a Goof dives into the story behind the making of the movie. Goofy Movie director Kevin Lima and other filmmakers share their stories and some never-before-seen archival footage of the production — including one small black dot that changed the movie’s fate.

From the get-go, A Goofy Movie was already running on a tighter budget than splashy Disney animated movies like The Lion King and Aladdin. It was specifically made as part of a push by Walt Disney Studios Chairman Jeffrey Katzenberg, who wanted the company making cheaper movies. So the production team was resourceful and scrappy — but they were aware even the most minor setback could be devastating.

As Lima recounts in the documentary, the filmmakers composited the film’s images digitally, putting them into a frame on a monitor, with a camera recording the monitor. They had gotten pretty far into the film recording process when someone suggested they should probably check out the footage they’d produced so far on a “big screen.”

During one of those screenings, someone noticed a little black dot that was consistent throughout the footage. The monitor they were using had a single dead pixel, which wasn’t noticeable on its own screen or on TV-screen-sized images. But blowing it up to theatrical-release size made the flaw obvious. The team was mortified.

A lot of the anecdotal scenes in Not Just a Goof are animated in the style of A Goofy Movie, with the filmmakers having their own Goof-sonas. In this one, a diligent Goofy-world-style filmmaker pores through all the movie negatives and realizes every frame of the completed footage has a missing pixel. Cue three Goofy-like figures bawling.

“It was so discouraging,” Lima says. “We had to go back and reshoot the entire movie again.”

So back to the drawing board — er, the filming process — the crew went. This time, though, they had to check and double-check and triple-check each shot to make sure they were all clean of abnormalities. It was tiring, demoralizing work, and the movie’s release date ended up getting bumped from November 1994 to April 1995. (Apparently the delay didn’t torpedo their shoestring budget — at least, they don’t address it in the documentary.)

But in retrospect, Lima says that missing that first release date was a relief. The team was already crunching, and they weren’t sure how they were even going to finish the movie. The reshoots gave them more breathing room, and in turn gave them the extra time they needed in order to make A Goofy Movie the best it could be.

“That little black dot saved our butts,” Lima says.

Not Just a Goof is streaming now on Disney Plus. (And so is A Goofy Movie).