Khan worm

This creature says of itself that it has no name yet as it is new. Dean says it is like a Khan Worm on steroids, and also refers to it as a "twelve inch long herpe."

The Khan Worm was created by Eve. It that can enter a person's body through the ear and control their actions. She plants it inside a trucker, who goes on to kill his family. It then passes to one of his co-workers who kills 12 people. While investigating the murders, it infects Dean who kills his cousin Gwen, and then infects Samuel, and finally Bobby who kills Rufus while possessed. While possessing Bobby, it tells Dean and Sam that it was created by Eve, who intends for supernatural beings to take over the world.