Firestarter - S4-E1
Visible crew/equipment: When Eli is at McShay's bar he hears the ghost beside him say, "Day after day after day," then when the bartender speaks to Eli, in the wide shots the shadow of the boom mic is visible right above the mirror. After Melinda walks in, when the bartender tells her that Eli scared all his business away, we can see in the mirror's reflection the boom mic dipping into view.
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