The polar bear in Mount Snow is a landmark in Kart Kingdom that was added in 2016 during the second Odd Squad party. In the blog post, "Be Nice To Polar Bears!" K said that Kart Kingdom is lucky to have polar bears in the kingdom. Then K said to get a selfie by it. It was a popular landmark.
Unfortunately, it was removed afterwards. It is unknown if the creators removed it or hackers did.
K wrote in the blog post Dear K Answers! that the polar bear left, but this might be a cover-up story until the issue is fixed.As of the April 2018 update, the polar bear has reappeared in Mount Snow, due to many requests.