'The Hunt for Gollum' Short Film Back Up on YouTube After Getting Yanked

There's a new 'Lord of the Rings' movie coming out that's all about Gollum -- and amid the news, a famous short film about it got yanked ... only to be revived on YouTube a day later.

A viral short film called "The Hunt for Gollum" -- which got uploaded to YT about 15 years ago -- has been praised among Tolkien fans for years as a stellar piece of fan fiction and art, which while not sanctioned by Warner Bros., still held its own and looked damn good.

On Thursday, WB announced they were making a brand new installment to their film franchise with the same title -- which led to the short being taken down on a copyright claim ... but it seems Warner has backed off, 'cause about 12 hours or so later, it's up again!

Indeed ... word of the short receiving a copyright complaint on YouTube went around like wild fire on the heels of the 'Gollum' movie announcement ... and people were all riled up.

The reason ... many felt it was unfair to force the short to act like it never existed, because it was technically here first -- and it's been around for well over a decade. Fanboys cried foul!

In terms of the why for the change of heart -- well, turns out it was actually a mistake on WB's part. Sources with direct knowledge tell us the copyright claim got applied in error ... and the studio realized that, so they removed it and YouTube did their thing.

The director of the short, Chris Bouchard, uploaded an email he got from YT saying the copyright claim had been released ... confirming WB retreated all on their own. He tells TMZ ... "We’re just happy to hear folks remembered our film somewhat fondly, low-fi effort that it is. And grateful as of course fan films are in strange legal territory."