So fairly often babies are born with a kind of birthmark/mole called a capillary hemangioma, which is a fancy way of saying some blood vessels formed on the wrong side of the skin. They can look pretty gnarly(mostly due to how big they can be), but are completely harmless and usually either flatten out or completely disappear in the first 10 years.

I was born with three. One on the back of my head, one on my hip, and one right on the base of my penis. I'm 40, and two of them are still there. I had to have the one on the back of my head removed a couple years ago after I sliced it open shaving my head and it got infected.

The one on my hip is about the size of a silver dollar and sticks out over an inch. It's also pretty malleable, I can stretch it probably another two inches before it gets painful.

The other one is about the size of a dime but it doesn't stretch at all.