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A seemingly innocuous men's boot available from a retailer on Amazon has been recalled after a Redditor discovered it left a tread print that looked a lot like a swastika.

Earlier this week a user on the site posted an image of their newly purchased New Men's Polar Fox Winter Cap Toe Wool Lining Boot. A side-by-side shot showed the print the tread left.

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The uploader captioned the photo, which has since had over three million views, "There was an angle I didn't get to see when ordering my new work boots..."

Redditors traced the boot to its Amazon page and started inundating the listing with questions, comments, reviews and posts about the swastika design — as well as some ill-advised puns about Hitler, the Holocaust and Nazis.

The Amazon listing for the boot has since been pulled down, but a cached version shows an image of the tread for the $50 boot made by Conal Footwear. A photo on Amazon shows its rubber sole.

Image: screengrab/amazon

Conal Footwear, a company based in Southern California, posted on its website it had recalled and stopped selling the shoe a few days after the original Reddit post went up.

It wrote that it had been informed that the boots "have an offensive symbol designed on them" and wanted to immediately apologize. "We are extremely sorry for the frustration this has caused our customers and the public."

It said the design was not intentional and blamed it as a mistake from manufacturers in China, adding, "We would like to issue our sincerest apologies to our customers and to anyone who was offended by the swastika imprint that the boots left behind." The company "does not promote hate or discrimination of any kind," the statement continued.

Sure enough, the shoe is no longer available on Amazon or other shoe-selling websites.

Goes to show, good to check what's underfoot.