Heart & Soul - S4-E8
Continuity mistake: After Sam reads the newspaper article about Jim's death it cuts to him dropping in to see Melinda, and when he's looking at the framed photographs on the sideboard two of the closeups of the photos are flipped shots - the positions of the frames are reversed.
Continuity mistake: While Melinda's trapped underground with the rising water flooding the utility vault, when Eli and Jim go down below Eli takes off his shoes and jacket, the camera pans up from the churning water and we briefly see Eli's bare feet. The next shot we see him taking the socks off.
Imaginary Friends and Enemies - S4-E6
Continuity mistake: In the scene in the woods where we first see Owen's ghost, as the camera cuts back and forth between Melinda talking to Owen and what her friend sees, the two women are alternately closer and then significantly farther apart. They're supposed to be standing basically in the same spots, only taking maybe one or two small steps during Melinda's conversation with Owen.
Continuity mistake: When Eli tries to use a card to open Zoe's door, the card breaks. He is holding on to the larger piece of the card in his right hand when this happens and the smaller piece is in the frame. He gets the other piece and the shot changes to him suddenly holding the smaller piece in his left hand, as well as the card having been flipped around (the strip is seen in both shots, and the two shots face in opposite directions).
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