#3. If your tongue is black and hairy
Much like hair, the papillae on your tongue grow throughout your lifetime. In some people, they become excessively long, which makes them more likely to harbor bacteria. When these bacteria grow, they may look dark or black, and the overgrown papillae can appear hair-like. Fortunately, this condition is not common and is typically not serious. It’s most likely to occur in people who don’t practice good dental hygiene.