Observer Effect (Star Trek: Enterprise)

"Observer Effect" is the eleventh episode of the fourth season of the American science fiction television series Star Trek: Enterprise and the eighty-eighth overall. It was first aired on January 21, 2005, on UPN. It was written by Judith and Garfield Reeves-Stevens, and directed by Mike Vejar. Set in the 22nd century, the series follows the adventures of the first Starfleet starship, Enterprise, registration NX-01. This episode sees alien entities test the Enterprise crew by observing their reactions to a deadly silicon-based infection. Actual first contact with these aliens – the Organians – would occur about a century later, during the events of the original series Star Trek episode "Errand of Mercy".

As it was a bottle episode, the episode did not use any additional sets or guest stars with the intention of cutting down on costs for the series. This also gave time for the visual effects team to finish earlier work. The episode received mixed reactions from critics, with praise directed at the links to the original Star Trek series, while criticism directed towards some of the characterization of the characters. "Observer Effect" was watched by 2.76 million viewers on first broadcast, which formed part of an overall drop of viewers for the series.