Stopover in a Quiet Town - S5-E30
Visible crew/equipment: When the camera pans to Rod Serling for his opening narration, you can very briefly see several crewmembers and some backstage equipment.
Living Doll - S5-E6
Visible crew/equipment: The boom mike shadow is visible above Annabelle, after she tells Christie that Linda is at the door.
Living Doll - S5-E6
Visible crew/equipment: When Talky Tina calls Erich, the camera zooms in as Erich starts talking - and its shadow appears on his arm.
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.