Dean and Sam are hunting a Lamia, which is the same creature from Drag Me to Hell (2009), the movie mentioned by Bobby's neighbor, Marcy.
Alan Ackles, Jensen Ackles's father, has an uncredited part as the voice of a newscaster heard on Bobby's TV. Jensen Ackles had seen the part on the script and thought his dad could do it. The part was recorded over the phone as Alan Ackles sat in the studio in his house in Texas, in his bathrobe, sipping his coffee.
When Dean calls Bobby, the caller ID shows the name John P. Jones. John Paul Jones was a member of Led Zeppelin - Dean's favorite band.