UPDATE 10:09 AM PT -- According to the Ellis County Wild Game Dinner organization, the guitar was donated to the auction before Taylor Swift ever made her Kamala Harris endorsement.

A certificate of authenticity confirms Taylor did sign the instrument, which was donated to the auction by a third party. The donation was not intended for destruction ... but the buyer paid for the item and chose to smash it up himself.

The Ellis County Wild Game Dinner is a non-profit supporting agricultural education for local youth, and the money went to a good cause.

There was a whole load of teardrops on one of Taylor Swift’s old guitars -- after a man bought her prized instrument at auction ... only to immediately smash it to smithereens!

The footage is going absolutely viral, showing a white-haired dude grabbing a hammer and going full demolition mode on the autographed guitar -- after dropping $4,000 on the instrument.

You can hear him giggling like a kid in a candy store, totally relishing the chaos. At one point, it looked like he was about to raise the guitar over his head to smash it to the ground ... before the host snapped him back to reality.

The video started blowing up Monday -- the scene appears to be from an event called the Ellis County Wild Game Dinner held outside Dallas, Texas Sunday night.

People are speculating it might be tied to politics -- especially since Taylor recently endorsed Kamala Harris for president.

The man's antics have sparked a major debate online ... with some cheering him on and others saying he could’ve spent that cash in way better ways.