Over Memorial Day Weekend, Joe and I saw Bug. Early in the movie, you hear a noise kinda like a cricket chirping (which is what they thought it was). After looking for it, they determine the cause was the smoke detector in the motel room. The believe the battery was dead, so they try to take it off the ceiling, but they can’t get it loose, so they whack it w/ a magic 8 ball, and it falls to the floor. HOWEVER, it’s not battery operated, because it’s got wires connected to it (3).
And not to spoil the ending, but yes, a fire does erupt at the end of the movie, and they never replace the detector (they throw out the old one)…