Ghost in Space

Something invisible is plaguing the crew of the Jupiter 2 at night and Dr. Smith becomes obsessed with the idea that it is the vengeful spirit of his deceased Uncle Thaddeus, with whom he frequently communes. This is one of those episodes where things just happen as the 'plot' demands with little logic or internal consistency. Dr. Smith suddenly becomes a spiritualist and the spaceship seems to have all the accoutrements needed for 19th century séance. Once again Penny comes across as a credulous child (while younger brother Will gets to be a precocious genius) and Maureen's primary duties seem to be as a seamstress (when she can take time from cooking and cleaning). The obligatory monster is pretty good but can't rescue a generally silly 'Smith-centered' episode.