Jess-Belle - S4-E7
Trivia: Jess-Belle was supposed to turn into a tiger instead of a leopard, but director Buzz Kulik auditioned dozens of tigers and told writer Earl Hamner, "Not one of 'em can act; can we make it another animal?" The cat that got the job had problems too. After Kulik put his crew inside a cage to protect them from the "vicious" beast, the mildly-tranquilized trained leopard missed his walking and leaping cues and kept falling asleep. (00:33:30)
Trivia: This was the only hour-long TZ episode never put into syndication. At the time the series was originally syndicated, "Miniature" was involved in a lawsuit due to an earlier script being submitted that dealt with inanimate figures coming to life. The suit claimed that "Miniature" had stolen the idea. The case was dismissed by the initial judge and on appeal, but the damage was done. The episode was aired only twice, on February 21, 1963 and again in 1984 as part of the "Twilight Zone Silver Anniversary Special"; however, the episode is available on DVD and on streaming platforms.
He's Alive - S4-E4
Trivia: If Nick looks familiar, it's because he's played by Howard Caine, the actor who makes a number of appearances on Hogan's Heroes, most notably as Gestapo Major Wolfgang Hochstetter.
Trivia: In this episode, the little girl's father is played by James Doohan, better known as Commander (later Captain) Montgomery "Scotty" Scott, Chief Engineer of the U.S.S. Enterprise.
Answer: It's explained in the episode. The aliens are experimenting to see how humans react to various scenarios. This just happens to involve them using super strength.
Thanks. It's been a long time since I saw the episode so I forgot.