He better watch out.

Footage of a heated confrontation between customers apparently taken inside a Costco emerged the day before Thanksgiving — sparking online debate about naughty shopper behavior as gift-buying season gets underway.

An aggravated man rammed a woman’s shopping cart with his own as he impatiently tried to push through a sea of shoppers in an aisle, according to a video a fellow customer posted on a Reddit Costco thread, which is not affiliated with the mega-chain store.

Staring down the logjam, the man, who had a small dog with him, talked about people needing to get out before he went cart-to-cart with the woman, according to the video.

The woman initially attempted to push back before the man plowed past her with the cart.

“You’re going to lose that battle,” he said as an employee asked him to calm down.

It was not immediately known what led up to the confrontation.

It’s also unclear when or where the showdown happened, but it was posted online Wednesday as shoppers looked to pick up last-minute items for their Thanksgiving feasts.

“There’s nothing I want less than to be in a Costco near a holiday,” one Redditor wrote. “People are already the worst there, I can’t imagine how awful they would be the day before Thanksgiving or Christmas.”

The footage sparked comments about proper shopper etiquette, with posters stating, “He shouldn’t be acting that way, but … why are there 3 carts blocking the aisle?”

“I mean I feel that way when people block aisles but I could never act like that [for real] lol,” another account stated.

“The way he reacted was wrong but why are so many people just standing around in the middle of the store not allowing people to get through?” an additional poster wrote.

“Okay but seriously why is everyone blocking the aisle?” another social media wondered.

Some online posters also criticized the impatient man for bringing a dog to the warehouse store.

“Ugh, I hate when people bring animals inside grocery stores,” one seethed.

A request for comment from Costco was not immediately returned.

While Costco is closed on Thanksgiving, it reopens for Black Friday.

One Reddit user astutely stated, “God bless all the Costco workers this holiday season.”