A Hundred Yards over the Rim - S2-E23
Visible crew/equipment: When Christian walks up to the man in front of the diner, you can see a crew member in a plaid shirt and white pants reflected in the man's sunglasses.
Visible crew/equipment: An equipment shadow moves across the back of Ellington's coat as Brother Jerome is telling him how the Devil was captured. (00:14:30)
The Trouble with Templeton - S2-E9
Continuity mistake: When Booth grabs her, Laura's long string of beads breaks. When she starts dancing a moment later, though, they've somehow repaired themselves. (00:18:50)
Visible crew/equipment: When Sykes opens the Sheriff's office door to leave, the "sky" outside has a very large equipment shadow on it, hanging over the building across the street. (00:05:10)
The Lateness of the Hour - S2-E8
Visible crew/equipment: As Robert is pouring Dr. Loren's drink, an equipment shadow moves across the top of Jana's head in the foreground. (00:08:20)
The Lateness of the Hour - S2-E8
Visible crew/equipment: When Jana is screaming "No pain!" at the top of the stairs, a film crew member's shadow can be seen moving on the wall behind her. (00:22:30)
King Nine Will Not Return - S2-E1
Continuity mistake: Embry soaks the front of his shirt with water from the canteen. But when he runs toward the B-52's cockpit and turns around a moment later, his shirt is completely dry again. (00:10:10)
Nervous Man in a Four Dollar Room - S2-E3
Continuity mistake: The unconscious Jackie changes positions on the bed between the overhead shot and the next one, taken from ground level. (00:13:45)
A Most Unusual Camera - S2-E10
Revealing mistake: The crooks in this episode appear to have obtained the same pile of funny money that the Castles received in "Man in the Bottle." The bills don't even vaguely resemble any real U.S. currency. (00:20:25)
The Rip Van Winkle Caper - S2-E24
Factual error: When they looked at Mr. Herbie's case, they only saw the skeleton. Problem is the clothing was missing, where there should have been some remnants. And the vehicle started with no trouble. After a hundred years, the battery should have been dead, and the engine inoperable.
A Hundred Yards over the Rim - S2-E23
Continuity mistake: When Joe (the diner owner) hands Christian Horn the glass of water, Horn grabs it by the base of the glass and drinks from it holding it the same way, almost to the last drop. The camera quickly switches the angle to show Horn finishing it close up, but this time he's holding it with his fingers wrapped around the glass. The camera switches the angle again as he's handing it back to Joe, once again holding it by the base.
Revealing mistake: The woman leads a simple but hard life, however, in several close ups, she has long, tapered, finely manicured and polished fingernails.
Will the Real Martian Please Stand Up - S2-E28
Continuity mistake: During the scene in the diner between Ross the Martian and Haley the Venusian, there are objects such as a napkin dispenser visible on the counter over the left arm of Haley, which then disappear in the shots over Ross' right arm.
Continuity mistake: Hunnicut puts a cigar on the bar rail when going to talk to a couple, but during the opening narration in the same spot, it's missing.
A Thing About Machines - S2-E4
Revealing mistake: When the electric razor is coming down the stairs after Finchley, the wire used to pull it is visible. (00:19:50)
The Odyssey of Flight 33 - S2-E18
Continuity mistake: When the plane first descends, the headphones that the radio controller is wearing keep moving from his neck to head.
Audio problem: Throughout Corwin's scene with the two children on the street, and through Rod Serling's subsequent introduction to the episode, you can hear the loud hiss of fan blowers used to waft artificial snow onto the set. (00:04:50)
Revealing mistake: Mr. & Mrs. Castle wish for a million dollars in 5 and 10 dollar bills. But the bills they receive all have the same pattern printed on both sides, a pattern which which doesn't resemble any real US currency. There's also not nearly enough of the bills to total a million dollars. (00:12:30)
Mr. Dingle, the Strong - S2-E19
Revealing mistake: Dingle lifts the bar bully over his head and twirls him around. But The Dummy used to achieve this effect has a distinctly lifeless, plastic face, and more than once, the wires suspending it are visible. (00:18:00)
Revealing mistake: The sky behind the hanging scene at the end has several prominent wrinkles in it, betraying the fact that it's not a sky, but a cloth backdrop. In some shots, you can also see shadows on the cloth. (00:19:00)
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.