You may think of your belly button as just a scar from your umbilical cord, but it's actually a bustling hub for bacteria. A ...

The human belly button. Image credit: DreamBig/Shutterstock.com If you've ever been pregnant, you may well have discovered a blackened mass called a navel stone protruding from your belly button.

Your belly button is a scar, your very first one. It forms when a doctor snips your umbilical cord, and, depending on how it heals, you could have an outie or, more likely, an innie.

One clip, posted at the end of November, has over 3.2 million views with the caption, “When you think the navel is just for collecting dirt,” and several images of his modified belly button.

If you have a lump or mass in your belly button, you should see a doctor. They can examine it and make sure it isn’t something more serious, such as skin cancer. If it's a cyst, you may need to ...