Updated

Walmart found itself on defense this week following the discovery of a mug with a controversial slogan for sale on the superstore’s website.

Company JM Holdings, a third-party vendor, was selling a mug with the words “got retard?” emblazoned on the side, the company confirmed to FoxNews.com. The item, which was also briefly available on Amazon.com, was promptly removed from Walmart’s website Monday morning-- but not before creating a stir on social media from concerned parents and special needs advocates.

The product also caught the attention of State Senator Ted Kennedy Jr.

A Walmart spokesman could not verify how long the item had been available for sale online but said the post "clearly violated our prohibited items policy and once it was brought to our attention, we quickly removed it from the Marketplace. We think it’s unacceptable a seller put it on the site in the first place."

When reached by FoxNews.com, an Amazon.com spokesman said the mug was "not listed for sale on Amazon" and would not elaborate on how the item ended up on the site. Other items, including apparel, with the phrase "got retard?" were available through Amazon's Marketplace early Tuesday but have since been removed from the site.

Sara Hart Weir, president of The National Down Syndrome Society, told Vocativ that both Walmart and Amazon agreed to remove the mugs after being contacted.

“NDSS strongly condemns the use of the ‘r word,'” Weir said.  “As the leading human rights organization for all people with Down syndrome, we maintain a zero tolerance policy for this type of mockery and offense. All people with Down syndrome are valued members of society and deserve to be treated with the upmost dignity and respect.”

Walmart's prompt response was met with gratitude from at least one concerned parent.

"As a parent of a child with special needs I'm thankful to see them remove the item so quick and hope our world continue to learn to see the value and with of all humans," Rick Smith, a father of a child with Down Syndrome and the creator of the blog Noah's Dad, told FoxNews.com.

JM Holdings said the mug's design was created accidentally, as many of its products are produced via “lists of words taken directly from the dictionary.” The company argued that they try their best to cut potentially offensive terms, but noted that “some words do slip through the cracks.”

There may be a lot of cracks to slip through; the company was also selling a “color changing coffee mug” with the phrase “got hitler?” but that item has also since been removed.

Walmart is currently reviewing JM Holdings’ full inventory.