I definitely did this to my parents once(or twice...). We had this long hallway that ran from their bedroom past mine and my sisters that I used to race back and forth in(making the air move behind me was very entertaining). After a previous house fire and remodel, all the door knobs in our house were replaced with handles that were considerable more 'sharp'.

One night when I was 7 my dad had left his closet door slightly further open than usual, and I simply tried to run around it but ended up hitting my head on that handle. Queue immediate ER trip after I bled all over my parents' bed for a minute or two.

I'm pretty sure they put me under general anesthesia, and my mom remembers me being tied up in this little sack thing while they closed it up. I've still got a scar near where my hair parts on one side.