Democratic presidential candidate Joe Biden is often criticized for his confusions and mistakes in public speaking, in one of the most recent ones he said, “A black man invented the light bulb, not a white man named Edison.”

“People fear what is different. For example, why in God’s name do we not teach history in history classes? A black man invented the light bulb, not a white man named Edison,” Biden said in Kenosha, Wisconsin, on Sept. 3, according to Fox News.

Historically, American Thomas Alva Edison patented the incandescent light bulb in 1879. Later, African American Lewis Howard Latimer improved it by increasing its lifetime and joined Edison’s team.

During the same tour in Kenosha, Biden deviated from the topic he was dealing with in one of his speeches and while he was talking about taxes he said “they’ll shoot me,” without giving any explanation.

Both President Donald Trump and Biden visited Kenosha, the city shocked by the paralysis of African American Jacob Blake due to the shooting by a policeman. This event caused riots and the destruction of business establishments in the city.

With less than two months to go before the Nov. 3 presidential election, President Trump and Biden are campaigning for the next four-year term in the Oval Office.

According to recent polls, the results favor Trump, while Biden is losing ground with voters.

Among the most critical aspects of Biden’s Democratic campaign are his radical leftist leanings and his mental acuity.

Trump believes that in order to maintain his normal discourse Biden would be using some kind of drugs, so he proposes that both of them undergo tests to detect the content of foreign substances in their bodies.

“We’re going to call for a drug test, by the way, because his best performance was against Bernie. It wasn’t that he was Winston Churchill because he wasn’t, but it was a normal, boring debate,” Trump said, according to the Washington Examiner, referring to the improvement he noticed in Biden’s debate with Bernie during the primary.

In a tweet, internet user @NFLCFLTAXI adds a short video in which a mark can be seen on Biden’s left hand, during one of his speeches on Kenosha.

“Needle marks on Biden’s left hand,” noted @NFLCFLTAXI in his tweet.