Vampire pixies.

Shelby was bitten by a vampire pixie.  I think.  It went like this. 

All of a sudden I heard a shriek. Shelby was screaming "Something bit me! I was bitten!  Someone bit me!  You bit me!"  At that point I had seen where she was bitten. I thought she had poked holes in her hand with a pencil. She thought that she was bitten by a leprechaun. Then I came up with the revelation of the vampire pixie. It all added up.  There is no other possibility. It is the only explanation.  Shelby was bitten by a vampire pixie.  That or she was leaning on my zipper to my coat and it made a tooth pattern on her hand.  But I don't think so. 

Parker and Shelby.

P.S.

Look out for vampire pixies. And leprechauns. And angry coat zippers.