Character mistake: When Aiden and Melinda go the the hospital to visit Jim/Sam the picture on the hospital badge is of Jim Clancy not Sam Lucas... Jim has been in Sam's body for many years at this point. You can see the badge multiple times in the episode.
Character mistake: Jim is at the hospital - at the end of his phone conversation with Melinda, someone calls out "Dr. Clancy" when the character is Sam Lucas. (00:09:15)
Other mistake: When Rick suggests that the ghost may have had multiple personality disorder and that's why he's appearing as different people, Melinda says this isn't possible, because when someone dies they're free from all afflictions they had when they were alive. In season 2 episode 4, "The Ghost Within", the featured ghost has autism and is not able to verbally communicate or make eye contact with Melinda and we never see him freed from this mental affliction.
Continuity mistake: The lights over Melinda's shop appear and disappear all through the entire show.
Continuity mistake: After Delia and Melinda are at the house in the countryside the episode cuts to a scene at Same As It Never Was Antiques. In this shot out the front we can see Melinda's 2005 Jeep Liberty Limited edition parked, but Melinda hasn't had this since the first episode of season 3. From Season 3 episode 2 Melinda can be seen driving a 2007 Saturn Outlook XR. (00:04:50 - 00:39:51)
Continuity mistake: At the beginning of the episode when Jim and Melinda are watching the last of the movie, at one point Melinda takes a drink of her beer and crosses her arms twice but from a different angle.
Other mistake: The show was supposed to be on the East Coast, however you can see a reflection of a California Flag in Melinda's front windshield. (00:09:35)
Answer: This "spirit" appears in several episodes throughout the rest of the season including the season finale. He's a "bad spirit" that is intent on keeping souls trapped on Earth. With the death of Andrea (her business partner) he wanted to make a deal with Melinda, to give him HER soul to release everyone else including Andrea to cross over.
Boobra