Just call me "Daddy Zach"

When Dr. Smith got duplicated, I thought it was the best thing this show could've ever used. It showed us how much we need the bad side as well as the good side. The original Smith has both, but chooses to hide his good side and reveal his bad side, while the duplicate Smith just has the good characteristics, which made him seem hollow.

This one puts you in an odd position. It's difficult to argue persuasively for keeping the original Dr. Smith, who has lied to, betrayed, and endangered the lives of the Robinson family on any number of occasions, and sacrificing the replica Dr. Smith (not a robot, but a flesh and blood being, it should be remembered), who proves himself to be a trustworthy, valuable, and productive member of the crew. Even the alien isn't all that much of a bad guy, not wanting to abduct for sacrificial purposes a useful member of the party, but instead through guile selecting the one person who is more of a hindrance and liability to the castaways. I liked the performance of the actor playing the alien, too; he reminded me of the British comedian Peter Serafinowicz. But still, we all know what will happen, and why it must happen. I really am liking these b&w episodes on a cinematographic level, all those moody shadows really help ratchet up the tension and suspense. And Dr. Smith (the true, cowardly one) even gets some action here, liberating himself from the alien's ship. I didn't think he had it in him.

This was a fun episode in which we got to see a good Dr.Smith, however, he was as creepy as the bad Smith!

Love this episode. Harris's hilarious performance steals the show again. What made this show great was always its humor. Not its technical finesse and/or special effects. The story's were fun, exciting, and the cast sheer perfection. Especially for the mid-sixties turmoil.This show holds up. Many of the 60's shows are pretty bad. This one, like The Avengers, still works!!! Underrated because the messagey Star Treck stole the fans. But this show had the heart Star Trek always lacked.

I think this is one of the best and most touching episodes of the whole series! It's great to know a normal human being incapable of being perfect can have many faults and still be accepted (maybe even more than somebody with no faults at all)! It's also interesting to note the model of the ship used in this episode is the same model used for The Keeper's ship in Episodes 17 and 18 of Season 1)! :)