Penny finds the wreckage of a small spaceship. While exploring the area with Judy, she finds a dog and brings it back to the spaceship. One night, the dog runs away and Penny chases after it. She runs into a giant, hairy mutant who attacks Judy, but the dog saves the day.
original airdate--December 8,1965
Trivia--The title card shows that the Jupiter 2 has settled in the ground a few feet as compared to the first shows of the season.
- Why isn’t there some kind of technical manual on the Jupiter 2 that shows how to put the laser guns back together? If not, couldn’t they have asked the computer?
- What the heck happened to the dog? Everyone loves him, but after this episode we never see him or hear a single word about him ever again!
- Dr. Smith's personality undergoes a slight transformation from master villian to effete scoundrel as he initially believes the dog is actually a highly intelligent and threatening form of alien life disguised as a dog.