Last, and kind of least, moles. They’re something of a harmless anomaly. Usually, when skin cells grow, they spread out through the skin. A mole is what happens when the cells cluster instead of spreading out.

However, some moles can be a symptom of more alarming problems, which is why doctors will sometimes create “mole-maps.” By mapping out the moles on someone’s body and keeping track of them, it can catch symptoms earlier and help save lives.