According to David Lynch, BOB, the disembodied spirit who is ultimately responsible for Laura Palmer's death, was not always intended to be in the show. Originally it was supposed to be who was the murderer. The idea of BOB came about by accident. Frank Silva, who was working as a set dresser on the pilot was moving some furniture in Laura Palmer's bedroom and had moved a chest of drawers in front of the door. Someone jokingly warned him not to get stuck in the room and Lynch, who was standing nearby working on something else, had a vision of Silva locked in Laura Palmer's room. After finding out that Silva was also an actor, he decided to cast him in an as yet undetermined role in the show. On a whim Lynch filmed a panning shot of Laura's room with Silva hiding behind the bars of the foot of the bed. At this point he still did not know how he was going to use it. Later that day they were filming the scene where Laura's mother has a terrifying vision. They shot a shot where Mrs Palmer sits up bolt upright, terrified by what she's seen. Lynch was pleased by the performance but was informed by the director of photography that the shot was unusable because a crew member had been caught in the reflection in a mirror behind Mrs Palmer. When Lynch learned that the crew member was Frank Silva he was pleased and the idea of BOB as a malevolent spirit came about.

FILM CRIT HULK @FilmCritHULK
HAS ANYONE EVER ASKED WHY DAVID LYNCH NAMED LELAND PALMER AFTER ACTRESS LELAND PALMER?

IT THIS LAST PART THAT RITUALLY DRIVES HULK NUTS WHEN PEOPLE START INTERPRETING ART. HECK, THERE'S 90 MILLION LOST THEORIES OUT THERE THAT ARE BASED ON ONE DETAIL AND GO ON FOR PAGES AND PAGES WITHOUT EVER FITTING IN A LARGER CONTEXT OUTSIDE THE ARGUMENT (LOST "GURU" DOC JENSEN WAS PARTICULARLY HORRIBLE AT THIS). ONE MUST ALWAYS BE CAREFUL NOT TO JUMP OFF THE HANDLE INTO MEANINGLESS EXTRAPOLATION. ONE MUST CONSTANTLY ASK "HOW DOES THIS ALL PIECE TOGETHER?"